A “good fit” is considered to be one where the cation can touch: (a) all of its nearest neighbour anions.

A “good fit” is considered to be one where the cation can touch:

(A) all of its nearest neighbour anions.
(B) most of its nearest neighbour anions.
(C) some of its nearest neighbour anions.
(D) none of its nearest neighbour anions.

Option A is the correct answer. Explanation: A “good fit” is considered to be one where the cation can touch: all of its nearest neighbour anions.