How to write SQL below in order to display all details

While I am not 100% sure of the exact result that you want. Based on your existing query the issue is that you are using INNER JOIN on some of the tables when you should be using LEFT JOIN.

In your existing query you are using the following:

LEFT JOIN Image_Question iq 
  ON q.QuestionId = iq.QuestionNo 
INNER JOIN Image i 
  ON iq.ImageId = i.ImageId 
LEFT JOIN Audio_Question aq 
  ON q.QuestionId = aq.QuestionNo 
INNER JOIN Audio au 
  ON aq.AudioId = au.AudioId 
LEFT JOIN Video_Question vq 
  ON q.QuestionId = vq.QuestionNo 
INNER JOIN Video v 
  ON vq.VideoId = v.VideoId 

The problem is that the INNER JOIN is checking for matching records on all fields but you might not have a record that exists in the image, audio or video tables so it is not returning anything.

Based on your details your query should be similar to this:

select st.studentid,
  s.sessionid,
  s.sessionname,
  s.sessionduration,
  s.totalmarks,
  s.sessionweight,
  q.questionid,
  q.questionno,
  q.questioncontent,
  q.noofanswers,
  q.questionmarks,
  q.optionid,
  ot.optiontype,
  q.replyid,
  r.replytype,
  a.answerid,
  a.answer,
  ia.answermarks,
  p.penaltyenabled,
  pm.penaltyanswerid, 
  pm.penaltyanswer,
  pm.penaltymarks,
  i.imageid,
  i.imagefile,
  v.videoid,
  v.videofile,
  ad.audioid,
  ad.audiofile,
  m.moduleid,
  m.moduleno,
  m.modulename
from Student st 
inner join Student_Session ss
  on st.studentid = ss.studentid
inner join session s
  on ss.sessionid = s.sessionid
inner join question q
  on s.sessionid = q.sessionid
inner join answer a
  on q.questionid = a.questionid
inner join Individual_Answer ia
  on a.answerid = ia.answerid
left join Option_Table ot
  on q.optionid = ot.optionid
left join reply r
  on q.replyid = r.replyid
left join module m
  on s.moduleid = m.moduleid
left join Penalty p
  on s.sessionid = p.sessionid
left join penalty_marks pm
  on q.questionid = pm.questionid
left join image_question iq  -- note I am joining on both session and question
  on s.sessionid = iq.sessionid
  and q.questionid = iq.questionno
left join image i  -- this should be a left join not inner join
  on iq.imageid = i.imageid
left join video_question vq -- note I am joining on both session and question
  on s.sessionid = vq.sessionid
  and q.questionid = vq.questionno
left join video v  -- this should be a left join not inner join
  on vq.videoid = v.videoid
left join audio_question aq  -- note I am joining on both session and question
  on s.sessionid = aq.sessionid
  and q.questionid = aq.questionno
left join audio ad  -- this should be a left join not inner join
  on aq.audioid = ad.audioid
where  s.SessionId = 1
order by q.QuestionId 

See SQL Fiddle with Demo.

This is returning all of the data that you have requested above. Sample:

| STUDENTID | SESSIONID | SESSIONNAME | SESSIONDURATION | TOTALMARKS | SESSIONWEIGHT | QUESTIONID | QUESTIONNO | QUESTIONCONTENT | NOOFANSWERS | QUESTIONMARKS | OPTIONID | OPTIONTYPE | REPLYID | REPLYTYPE | ANSWERID | ANSWER | ANSWERMARKS | PENALTYENABLED | PENALTYANSWERID | PENALTYANSWER | PENALTYMARKS | IMAGEID | IMAGEFILE | VIDEOID |            VIDEOFILE | AUDIOID |          AUDIOFILE | MODULEID | MODULENO | MODULENAME |
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|         1 |         1 |         AAA |        01:00:00 |         30 |            20 |          4 |          1 |      Question 1 |           1 |             5 |        1 |        A-C |       1 |    Single |        1 |      A |           3 |              1 |               1 |             B |            1 |  (null) |    (null) |       1 | VideoFile/Speech.png |  (null) |             (null) |        1 |  CHI2513 |        ICT |
|         1 |         1 |         AAA |        01:00:00 |         30 |            20 |          4 |          1 |      Question 1 |           1 |             5 |        1 |        A-C |       1 |    Single |        1 |      A |           3 |              1 |               2 |             C |            1 |  (null) |    (null) |       1 | VideoFile/Speech.png |  (null) |             (null) |        1 |  CHI2513 |        ICT |
|         1 |         1 |         AAA |        01:00:00 |         30 |            20 |          5 |          2 |      Question 2 |           1 |             3 |        2 |        A-D |       1 |    Single |        2 |      C |           5 |              1 |               3 |             A |            1 |  (null) |    (null) |  (null) |               (null) |       1 | AudioFile/Song.png |        1 |  CHI2513 |        ICT |
|         1 |         1 |         AAA |        01:00:00 |         30 |            20 |          5 |          2 |      Question 2 |           1 |             3 |        2 |        A-D |       1 |    Single |        2 |      C |           5 |              1 |               5 |             D |            1 |  (null) |    (null) |  (null) |               (null) |       1 | AudioFile/Song.png |        1 |  CHI2513 |        ICT |
|         1 |         1 |         AAA |        01:00:00 |         30 |            20 |          5 |          2 |      Question 2 |           1 |             3 |        2 |        A-D |       1 |    Single |        2 |      C |           5 |              1 |               4 |             B |            1 |  (null) |    (null) |  (null) |               (null) |       1 | AudioFile/Song.png |        1 |  CHI2513 |        ICT |