S Block Elements

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

Assertion (A) : Lithium and beryllium unlike their other respective group members form compounds with pronounced ionic character.

Reason (R) : Lithium and Magnesium have similar properties due to diagonal relationship.

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