What comes next? DZA, FXC, HVE, ?

Correct — C.
Rule: 1st letter +2, 2nd letter −2, 3rd letter +2.

1st: D(4) → F(6) → H(8) → J(10)
2nd: Z(26) → X(24) → V(22) → T(20)
3rd: A(1) → C(3) → E(5) → G(7)

Next term: JTG → option (c).

Why the others are wrong

• (a)
  KSH — KSH moves each letter 3 places: H → K, V → S, E → H. The series moves by 2, giving J, T and G.
• (b)
  LRI — LRI moves each letter 4 places: H → L, V → R, E → I. That is double the series' step of 2.
• (d)
  IUG — IUG gets only the third letter right. I is H + 1 and U is V − 1, where the rule needs H + 2 = J and V − 2 = T.

Letter-cluster series are solved one position at a time. Read the first letters as a column, then the second, then the third, and find each column's step on its own.

Here two columns run forward and one runs backward, all by 2 places. The backward column starts at Z, the end of the alphabet, which is the cue to read it in reverse.

Key facts

• First letters D, F, H, J sit at positions 4, 6, 8, 10.
• Second letters Z, X, V, T sit at positions 26, 24, 22, 20.
• Third letters A, C, E, G sit at positions 1, 3, 5, 7.
• First and second positions add to 30 in each term: 4 + 26, 6 + 24, 8 + 22, 10 + 20.

Common traps

• Reading Z, X, V forward because the other columns go forward
• Spotting the direction but not measuring the gap, and stepping by 3 or 4

No directly related past PYQ was found.