Assertion : Photosensitivity of a metal is high if its work function is small.
Reason : Work function `= hf_(0)` where `f_(0)` is the threshold frequency.
A. If both assertion and reason are true and the reason is the correct explanation of the assert ion.
B. If both assertion and reason are true but reason is not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If the assertion and reason both are false