Three of the following alternatives follow a certain classification based on their method of sound production. Find the instrument that does NOT belong to the group.

Four letter-number pairs are given below. The pair on the left of (-) is related to the pair on the right with some logic. Three pairs follow the same logic, while one is different. Select the odd one out. (Note: Operations must be performed on whole numbers without breaking them down into digits).

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.)