Select the option that is related to the fifth term in the same way as the second term is related to the first term and the fourth term is related to the third term. CARBON : ACIYNO :: DAMAGE : ADNZEG :: MARGIN : ?

Correct — B. Split each six-letter word into three pairs and treat the pairs differently.

Rule: pairs 1 and 3 are swapped in place; pair 2 is replaced letter by letter with its alphabet opposite (position n becomes position 27 − n, so A↔Z, B↔Y).

CARBON → CA RB ON → AC + (R→I, B→Y) + NO = ACIYNO ✓
DAMAGE → DA MA GE → AD + (M→N, A→Z) + EG = ADNZEG ✓

MARGIN → MA RG IN
pair 1: MA becomes AM
pair 2: R is 18, so 27 − 18 = 9 = I, and G is 7, so 27 − 7 = 20 = T
pair 3: IN becomes NI

AM + IT + NI = AMITNI, which is option (b).

Why the others are wrong

• (a)
  MARGNI — MARGNI swaps only the last pair and leaves MARG untouched. Both of the other pairs change under the rule, one by swapping and one by substitution.
• (c)
  MATINI — MATINI converts pair 2 to the right letters, I and T, but writes them as TI and leaves MA unswapped. The swap belongs to pairs 1 and 3, never to pair 2.
• (d)
  AMGRNI — AMGRNI swaps all three pairs — AM, GR, NI — and never takes the alphabet opposite. RG has to become IT, not GR.

This is the fifth-term analogy: two worked examples, then one to imitate. The work is reading the examples closely enough to see that the six letters are handled in three blocks rather than as one string.

Two different kinds of operation sit side by side. A positional one — swapping the letters inside a pair — moves letters without changing them. A substitution one — the alphabet opposite, position n going to 27 − n — changes letters without moving them.

Write the alphabet out with its numbers before you start. The opposite pairs A–Z, B–Y, C–X and the rest are worth knowing cold, because they turn up in coding and odd-one-out too.

Key facts

• The transformation treats the six letters as three pairs, not as one string.
• Pairs 1 and 3 are swapped in place, so MA becomes AM and IN becomes NI.
• Pair 2 is replaced by alphabet opposites, position n going to 27 − n, so R becomes I and G becomes T.
• Applying all three steps to MARGIN gives AM, IT, NI — the answer AMITNI.

Common traps

• Applying the swap to all three pairs, which produces AMGRNI.
• Reading pair 2's change as a fixed forward shift rather than an opposite.
• Losing the pair boundaries and working across the six letters as one block.

No directly related past PYQ was found.