Analogy (letters) — “AB : ZY :: CD : ?”. Apply the mirror-letter mapping (A↔Z, B↔Y, C↔X, D↔W).

Introduction / Context:
AB maps to ZY via alphabet mirroring (A↔Z, B↔Y). Apply the same to CD.

Given Data / Assumptions:

• A↔Z, B↔Y, C↔X, D↔W.

Concept / Approach:
Replace each letter with its mirror counterpart.

Step-by-Step Solution:

Verification / Alternative check:
Order must be preserved; not reversed.

Why Other Options Are Wrong:
They show other letter pairs or reversed order.

Common Pitfalls:
Confusing mirroring with reversing the string.

Final Answer:
XW