Assertion : Intensity of `X` - rays can be controlled by adjusting the filament current and voltage.
Reason : The intensity of `X` - ray photons emitted per second from the target.
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If assertion and reason both are false.