The correct option is A 33 cm
We know that for a closed organ pipe, the resonate frequency is given by,
f=nv4l
For given frequency, for length to be minimum, n should be minimum i.e.(n=1).
f=v4l
Also, this fundamental frequency will be equal to the frequency of the tuning fork.
⇒264=3504l
⇒l=3504×264=0.33 m=33 cm