Answer and explanation

Correct answer: D. of

  1. Step 1: Capable is followed by of.
Answer
of.
Why not the others: for, to and at do not fit.

Practise more Structure, Grammar and Error Recognition.

Free questions with an explanation for every one, and full timed STEP (Standardized Test of English Proficiency) mock tests.

He is capable solving… | STEP (Standardized Test of English Proficiency)