material ui select option selected text code example
Example: material ui select helper text
<FormControl className={classes.formControl} error>
<InputLabel id="demo-simple-select-error-label">Name</InputLabel>
<Select
labelId="demo-simple-select-error-label"
id="demo-simple-select-error"
value={age}
onChange={handleChange}
>
<MenuItem value={10}>Ten</MenuItem>
<MenuItem value={20}>Twenty</MenuItem>
<MenuItem value={30}>Thirty</MenuItem>
</Select>
<FormHelperText>Error</FormHelperText>
</FormControl>