Assertion (A) : Ionisation energy `(I.E_(1))` of Ga is less than Al.
Reason (R) : Ga has a larger atomic size than Al.
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true but R is not a correct explanation of A
C. A is true but R is false
D. Both A and R are false.