The verified answer to “In a certain code, CODE is written as EDOC. The source working states: Correct answer: NIAR (Option B). Apply the same unchanged rule to RAIN: R→N, A→I, I→A, N→R. Therefore the required code is NIAR. Wrong options: SBJO is wrong because it does not reproduce the verified rule at every position; TCKP is wrong because it does not reproduce the verified rule at every position; QZHM is wrong because it does not reproduce the verified rule at every position. Even one mismatched position invalidates a code, so only Option B 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 NIAR. The alternatives TCKP, QZHM and SBJO fail because at least one position does not obey the same transformation. A useful final check is to map NIAR backward through the inverse operation and confirm that the original target is recovered.