Given below are two statements:one is labelled as Assertion A and the other is labelled as Reason R:
Assertion A:Late wood has fewer xylary elements with narrow vessels.
Reason R:Cambium is less active in winters.
In the light of the above statements,choose the correct answer from the options given below:

Options

A. Both A and R are true but R is not the correct explanation of A
B. A is true but R is false
C. A is false but R is true
D. Both A and R are true and R is the correct explanation of A.