Find out the pair which is different from the other given pairs :
ACow and Buffalo
BCock and Hen
CHorse and Mare
DDog and Bitch
ACow and Buffalo
BCock and Hen
CHorse and Mare
DDog and Bitch
Related Questions:
Based on the English alphabetical order, three of the following four letter-cluster pairs are alike in a certain way and thus form a group. Which letter-cluster pair DOES NOT belong to that group?
(Note: The odd one out is not based on the number of consonants/vowels or their position in the letter-cluster.)