A bulb is located on a wall. Its image is to be obtained on a parallel wall with the help of convex lens. If the distance between parallel walls is 'd' then required focal length of lens placed in between the walls is : -

Question

( A ) More than $\frac{d}{4} but\;less\; than \frac{d}{2}$
( B ) Less than or equal to $\frac{d}{4}$
( C ) Only $\frac{d}{4}$
( D ) Only $\frac{d}{2}$