Based on the English alphabetical order, three of the following four letter-clusters are alike in a certain way and thus form a group. Which is the one that DOES NOT belong to that group? (Note: The odd man out is not based on the number of consonants/vowels or their position in the letter-cluster.)

Correct — D. Turn each cluster into position numbers and read its two gaps.

Rule: back 2, then back 4, counting backwards and continuing at Z when you pass A.

FDZ → 6, 4, 26: 6 − 2 = 4, and 4 − 4 wraps past A to 26 (Z).
JHD → 10, 8, 4: 10 − 2 = 8, and 8 − 4 = 4.
AYU → 1, 25, 21: 1 − 2 wraps past A to 25 (Y), and 25 − 4 = 21.

KJE → 11, 10, 5: 11 − 1 = 10, and 10 − 5 = 5. Its gaps are 1 and 5, so KJE is the cluster that leaves the group — option (d).

Why the others are wrong

• (a)
  FDZ — FDZ obeys the rule: F(6) back two is D(4), and D(4) back four runs past the start of the alphabet to Z(26).
• (b)
  JHD — JHD is the cleanest member of the group — J(10) to H(8) to D(4), with no wrap needed anywhere.
• (c)
  AYU — AYU wraps at the front: A(1) back two lands on Y(25), and Y(25) back four is U(21). The wrap makes it look odd, but its gaps are the group's 2 and 4.

Odd-one-out among letter-clusters is position arithmetic. Write the three position numbers under each cluster and compare the two gaps; the group is whatever gap pattern three of them share.

Wrapping is the whole difficulty here. Counting backwards past A continues at Z, so A − 2 is Y and D − 4 is Z. Two of these four clusters need that wrap, and a candidate who refuses it will name one of them as the odd one.

The note rules out sorting on consonants and vowels, so the arithmetic is the intended route.

Key facts

• FDZ, JHD and AYU each step back two letters and then back four.
• Counting backwards past A continues at Z, so A − 2 is Y and D − 4 is Z.
• KJE steps back one and then five, which is why it leaves the group.

Common traps

• Naming AYU the odd one because its first step wraps past A.
• Refusing the wrap and treating D − 4 as impossible, which knocks out FDZ instead.
• Trying to sort the clusters by consonants or vowels, which the note expressly bars.

No directly related past PYQ was found.