Is the C programming language object-oriented?

If by "is C object oriented?" you mean "is C designed with facilities specifically to support object oriented programming?" then, no, C is clearly not object oriented.

You can program in an object-orientated style in more or less any language. (I think runtime polymorphism -- i.e. virtual methods -- requires a language that supports function pointers.)

Here are a couple of examples:

• A short summary of object-orientated style in C: http://www.emilmont.net/doku.php?id=c:object_oriented_c
• A comparison between the same program written in C and C++: http://www.eventhelix.com/realtimemantra/basics/object_oriented_programming_in_c.htm