If 'READ' is coded as 'SFBE', how is 'BOOK' coded?

Correct — A. Compare READ with SFBE letter by letter.

Rule: each letter moves one place forward (+1).

R → S, E → F, A → B, D → E, as given
B → C, O → P, O → P, K → L

So BOOK is coded CPPL, option (a).

Why the others are wrong

• (b)
  DQQM — DQQM moves every letter two places forward: B → D, O → Q, K → M. The example moves each letter one place, R → S, not R → T.
• (c)
  APPL — APPL moves B back to A but the other letters forward. The rule moves every letter the same way, so B becomes C.
• (d)
  AQQM — AQQM moves B back one place and O and K forward two. Neither step matches the +1 in READ → SFBE.

A letter-shift code moves every letter by the same number of places. Read the shift off the example, then check it on every letter: R → S, E → F, A → B, D → E are all +1.

Apply that one shift to each letter of the new word. The double O in BOOK becomes a double P in the code.

Key facts

• READ → SFBE is a uniform +1 shift.
• Under +1, B → C, O → P and K → L, so BOOK → CPPL.
• A uniform shift keeps double letters double.

Common traps

• Shifting by two places, not one, and choosing DQQM.
• Moving the first letter backward by mistake, which leads to APPL or AQQM.

No directly related past PYQ was found.