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 :

• A

  $A$ is false but $R$ is true

• B

  Both $A$ and $R$ are true and $R$ is the correct explanation of $A$

• C

  Both $A$ and $R$ are true but $R$ is NOT the correct explanation of $A$

• D

  $A$ is true but $R$ is false