In the following question, find the odd letter/number pair  from the given alternatives.

BDS – 3520 STL → 202113 NQP – 151817 CZQ → 42618

CZQ → 42618

B + 1 = 3; D + 1 = 5; S + 1 = 20 S + 1 = 20; T + 1 = 21; L + 1 = 13 N + 1 = 15; Q + 1 = 18; P + 1 = 17 C + 1 = 4; Z + 0 = 26 ; Q + 1 = 18( which is odd)