Which of the following letter-clusters will replace the question mark (?) in the given series to make it logically complete? WIX, VHW, UGV, TFU, ?

Correct — D. Rule: every letter moves back one place at each step.

First letters: W, V, U, T, S
Second letters: I, H, G, F, E
Third letters: X, W, V, U, T

Reading the three columns together gives SET, option (d).

Why the others are wrong

• (a)
  TEU — The middle letter E is right, but T repeats the first letter of TFU and U repeats its third. Two of the three columns have not stepped at all.
• (b)
  SFT — S and T are right; the middle column must step from F to E. F is simply the second letter of TFU left unchanged.
• (c)
  SEU — S and E are right; the third column must step from U to T. U is the third letter of TFU left unchanged.

A letter-cluster series is three independent series printed side by side. Split the terms into columns and read each column on its own.

Here all three columns run backwards by one, which is easy to see once the terms are split and almost unreadable while you are trying to treat the clusters as words.

The habit that pays is columnar: write WIX, VHW, UGV and TFU one under another, and the step in each column becomes visible without any alphabet counting at all.

Key facts

• Every column of WIX, VHW, UGV, TFU steps back by one letter.
• The next term is SET, since S = T - 1, E = F - 1 and T = U - 1.
• Letter-cluster series are read column by column, not as words.

Common traps

• Stepping the first letter and copying the rest from the previous term.
• Reading the series forwards, which returns UGV — a term already printed.
• Marking SET because it is an English word rather than because the columns produce it.

No directly related past PYQ was found.