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

Assertion (A) : The ionic radii of O^2$-$ and Mg²⁺ are same.

Reason (R) : Both O^2$-$ and Mg²⁺ are isoelectronic species.

In the light of the above statements, choose the correct answer from the options given below.

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