The verified answer to “In a certain code, TRAIN is written as USBJO. How will METAL be written in that code?” is NFUBM, option D. The source working states: Correct answer: NFUBM (Option A). Apply the same unchanged rule to METAL: M→N, E→F, T→U, A→B, L→M. Therefore the required code is NFUBM. Wrong options: OGVCN is wrong because it does not reproduce the verified rule at every position; LDSZK is wrong because it does not reproduce the verified rule at every position; KCRYJ is wrong because it does not reproduce the verified rule at every position. Even one mismatched position invalidates a code, so only Option A 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 NFUBM. The alternatives OGVCN, LDSZK and KCRYJ fail because at least one position does not obey the same transformation. A useful final check is to map NFUBM backward through the inverse operation and confirm that the original target is recovered.