Which of these words will come last in a dictionary?

Correct — D.
Rule: compare letter by letter until two words first differ.

All four begin b-e-n, so the 4th letter decides:
bench → c, bend → d, beneath → e, bent → t

Order: bench, bend, beneath, bent. T comes latest in the alphabet → option (d).

Why the others are wrong

• (a)
  bench — bench has c as its 4th letter, the earliest of c, d, e and t. It comes first of the four, not last.
• (b)
  beneath — beneath is the longest word, but length plays no part. Its 4th letter, e, comes before t, so it sits third, ahead of bent.
• (c)
  bend — bend has d as its 4th letter, which comes before e and t. It sits second, after bench.

Dictionary order compares words one letter at a time from the left. The first position where two words differ decides their order, and nothing after it matters.

Length matters in one case only: a word that is the start of a longer word comes first, so bend comes before bending.

Key facts

• The four words share b-e-n, so their 4th letters c, d, e and t set the order.
• Dictionary order: bench, bend, beneath, bent.
• A word that begins a longer word comes first: bend before bending.

Common traps

• Ranking by word length, which puts beneath last
• Comparing the last letters instead of the first letter where the words differ

No directly related past PYQ was found.