Concept:Each option is formed by two pairs of consecutive letters, with the second pair lying 3 letters before the first pair in the alphabet.Explanation:Check the pattern for each option.For GHDE: G→H is +1, D→E is +1, and G→D is −3, H→E is −3.For PQMN: P→Q is +1, M→N is +1, and P→M is −3, Q→N is −3.For BCYZ: B→C is +1, Y→Z is +1, and B→Y is −3 (circularly), C→Z is −3.For KLHI: K→L is +1, H→I is +1, and K→H is −3, L→I is −3.But RSTP gives R→S→T as three consecutive letters, not two consecutive pairs.So RSTP does not follow the same logic.Answer:C. RSTP