Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : There is a considerable increase in covalent radius from $\mathrm{N}$ to $\mathrm{P}$. However from As to Bi only a small increase in covalent radius is observed.

Reason (R) : Covalent and ionic radii in a particular oxidation state increases down the group. In the light of the above statements, choose the most appropriate answer from the options given below:

1. A (A) is false but (R) is true
2. B Both (A) and (R) are true and (R) is the correct explanation of (A)
3. C Both (A) and (R) are true but (R) is not the correct explanation of (A) Correct answer
4. D (A) is true but (R) is false