Which of the following terms will replace the question mark (?) in the given series? BHVC, ZLTG, XPRK, ? , TXNS

Correct — B. Rule: each of the four letter positions runs its own progression: 1st -2, 2nd +4, 3rd -2, 4th +4.

1st letters: B(2), Z(26), X(24), ?, T(20), falling by 2, so ? = 22 = V
2nd letters: H(8), L(12), P(16), ?, X(24), rising by 4, so ? = 20 = T
3rd letters: V(22), T(20), R(18), ?, N(14), falling by 2, so ? = 16 = P
4th letters: C(3), G(7), K(11), ?, S(19), rising by 4, so ? = 15 = O

The first column wraps: stepping two back from B(2) lands on Z(26).

The missing cluster is VTPO, which is option (b).

Why the others are wrong

• (a)
  VTPN — VTPN gets the first three letters right and misses the fourth. Column four runs 3, 7, 11, 15, 19, so the blank is 15 = O, not N at 14.
• (c)
  VPTO — VPTO has the second and third letters transposed. Column two must reach T(20) between P(16) and X(24), and column three must reach P(16) between R(18) and N(14).
• (d)
  VPTN — VPTN carries both errors at once, the middle letters transposed and N in place of O, so it fails on two of the four columns.

Letter-cluster series are solved column by column, never as whole words. Convert each position to its alphabet number, look for a constant step, then read the missing letter back out.

Here the four columns move at different rates, which is why the clusters look random. Two columns fall by 2 and two rise by 4.

Always confirm against the term after the blank as well as the term before. TXNS is 20, 24, 14, 19, and it verifies all four progressions at once, which turns a guess into a proof.

Key facts

• The four columns step by -2, +4, -2 and +4 respectively.
• Stepping two places back from B(2) wraps round to Z(26).
• The final given term TXNS reads 20, 24, 14, 19, which confirms every column.

Common traps

• Solving only from the term before the blank and never checking against TXNS
• Losing the wrap when the first column steps below A
• Writing the four right letters in the wrong order, which is what options (c) and (d) offer

No directly related past PYQ was found.