In the adjacent figure, line $$AB$$ is parallel to screen $$S$$. A linear obstacle $$PQ$$ between the two is also parallel to both. $$AB$$, $$PQ$$ and screen $$S$$ are coplanar. A point source is carried from $$A$$ to $$B$$, along the line $$AB$$. What will happen to the size of the shadow of $$PQ$$ cast due to the point source on the screen $$S$$

A

It will first increase and then decrease.

B

It will first decrease and then increase.

C

It will be of the same size for any position of the point source on the line $$AB$$.

D

Umbra will increase and penumbra will decrease till central position.