The verified answer to “In a certain code, HOUSE is written as GNTRD. How will SOUND be written in that code?” is RNTMC, option B. The source working states: Correct answer: RNTMC (Option C). Apply the same unchanged rule to SOUND: S→R, O→N, U→T, N→M, D→C. Therefore the required code is RNTMC. Wrong options: TPVOE is wrong because it does not reproduce the verified rule at every position; UQWPF is wrong because it does not reproduce the verified rule at every position; QMSLB is wrong because it does not reproduce the verified rule at every position. Even one mismatched position invalidates a code, so only Option C is correct. This observation must be confirmed across every available letter position or every consecutive term before it is applied to the missing code. Applying the verified rule to the target expression produces RNTMC. The alternatives UQWPF, QMSLB and TPVOE fail because at least one position does not obey the same transformation. A useful final check is to map RNTMC backward through the inverse operation and confirm that the original target is recovered.