The verified answer to “In a certain code, FISH is written as EHRG. How will PORT be written in that code?” is ONQS, option B. The source working states: Correct answer: ONQS (Option C). Apply the same unchanged rule to PORT: P→O, O→N, R→Q, T→S. Therefore the required code is ONQS. Wrong options: QPSU is wrong because it does not reproduce the verified rule at every position; RQTV is wrong because it does not reproduce the verified rule at every position; NMPR 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 ONQS. The alternatives RQTV, NMPR and QPSU fail because at least one position does not obey the same transformation. A useful final check is to map ONQS backward through the inverse operation and confirm that the original target is recovered.