Find the next alphabet in the sequence: A, Z, B, Y, _, X

Concept: Some alphabet series interleave two independent sub-sequences. Reading alternate positions (1st, 3rd, 5th, ...) gives one sequence, and the remaining positions (2nd, 4th, 6th, ...) give a second, separately patterned sequence. Solve each half on its own, then combine.

1. Split the six given terms by position: the odd positions (1st, 3rd, 5th) are A, B, _ and the even positions (2nd, 4th, 6th) are Z, Y, X.

2. The even-position half moves backward through the alphabet one letter at a time: Z, then Y, then X, confirming that half simply counts down from Z one step per term.

3. The odd-position half moves forward through the alphabet one letter at a time: A, then B, so the next term continues the same forward step to give the letter immediately after B.

4. That forward step gives the missing fifth term.

Cross-check: with the missing term filled in, the six-term series reads A, Z, B, Y, C, X — the odd-position half (A, B, C) increases by one letter each step and the even-position half (Z, Y, X) decreases by one letter each step, with no inconsistency between the two halves.

The missing term is C.