If SNAKE is written as RMZJD, how is ZEBRA written.

Correct — A.
Rule: each letter moves back one place (−1), with A wrapping round to Z.

SNAKE → RMZJD: S→R, N→M, A→Z, K→J, E→D.
ZEBRA: Z→Y, E→D, B→A, R→Q, A→Z.
Code = YDAQZ → option (a).

Why the others are wrong

• (b)
  YDAQY — YDAQY slips on the last letter. A − 1 wraps round to Z, as SNAKE's A → Z shows; Y would be two places back.
• (c)
  YCBQZ — YCBQZ breaks the −1 in the middle: E − 1 is D, not C, and B − 1 is A, not B.
• (d)
  YDAQX — YDAQX ends in X, three places back from A. The code moves every letter back by one, so A becomes Z.

In a letter-shift code, write the positions (A = 1 … Z = 26) and find the change for each letter of the given pair. When every letter moves by the same amount, apply that shift to the new word.

The alphabet is treated as a circle: one place before A is Z. SNAKE's A → Z shows this code uses the wrap.

Key facts

• Here the code is −1 for every letter: SNAKE → RMZJD.
• Moving back one place from A wraps round to Z.
• Letter positions used here: A = 1, B = 2, E = 5, R = 18, Z = 26.

Common traps

• Missing the wrap and writing Y or X for A − 1.
• Checking only the first letter, which all four options share.

No directly related past PYQ was found.