Classification – Letter triplets: pick the odd one out where the first to second jump is +2 and the second to third jump is +3 (A=1 … Z=26, cyclic if needed). Three triplets follow +2 then +3; one does not. Which triplet is different? Options: CEH, KMP, XZC, NPT.

Introduction / Context:
Triplet sequences frequently embed two fixed jumps. Recognizing the increment sizes (+2 then +3 here) helps isolate the single violator.

Given Data / Assumptions:

• Alphabet index A=1 … Z=26; treat Z→A with wrap for addition.
• Triplets: CEH, KMP, XZC, NPT.
• Target rule: first→second = +2; second→third = +3.

Concept / Approach:
Compute consecutive jumps per triplet and compare with the rule.

Step-by-Step Solution:
C(3)→E(5)=+2; E(5)→H(8)=+3 ✔K(11)→M(13)=+2; M(13)→P(16)=+3 ✔X(24)→Z(26)=+2; Z(26)→C(3)=(+3 with wrap) ✔N(14)→P(16)=+2; P(16)→T(20)=+4 ✖

Verification / Alternative check:
Recompute with a quick index list; only NPT breaks the +3 second jump.

Why Other Options Are Wrong:
CEH, KMP, XZC: All satisfy +2 then +3 (with cyclic wrap in XZC).

Common Pitfalls:
Forgetting cyclic wrap at Z, or miscounting steps by including the starting letter twice.

Final Answer:
NPT