Which letter-cluster will replace the question mark (?) to complete the given series? ZVRN, VSPM, RPNL, ?, JJJJ

Correct — B.

Rule: read the clusters column by column, not as words. Column 1 falls −4, column 2 −3, column 3 −2, column 4 −1.

Column 1: Z(26), V(22), R(18), N(14), J(10)
Column 2: V(22), S(19), P(16), M(13), J(10)
Column 3: R(18), P(16), N(14), L(12), J(10)
Column 4: N(14), M(13), L(12), K(11), J(10)

The missing cluster is N M L K, option (b). Every column lands on J at the fifth term, which is the check the question builds in.

Why the others are wrong

• (a)
  RNLL — It opens with R, the first letter of the previous cluster, so the −4 step has not been taken at all. Its last letter L also misses the −1 step down to K.
• (c)
  RMLN — The middle two letters are right, but it opens with R instead of N and closes with N instead of K, so columns 1 and 4 have not been stepped.
• (d)
  RNLK — Its last two letters are right; the failure is at the front. Column 1 must fall −4, from R to N, and column 2 must fall −3, from P to M — (d) gives R and N.

Letter-cluster series are worked in alphabet numbers. Convert each letter to its position, read down each column, and the pattern declares itself.

The four columns here fall at four different rates — 4, 3, 2 and 1 — which is why ZVRN, VSPM and RPNL look unrelated as words. Nothing in the clusters is meant to be read horizontally.

The last term, JJJJ, is the give-away. Four columns that finish on the same letter must be closing at different speeds.

Key facts

• The four columns of this series fall at −4, −3, −2 and −1 per step.
• The completed series is ZVRN, VSPM, RPNL, NMLK, JJJJ.
• All four columns converge on J at the fifth term.

Common traps

• Trying to read the clusters as words instead of as columns
• Assuming every column moves at the same rate
• Losing a place while counting backwards through the alphabet

No directly related past PYQ was found.