In the following questions, a sentence or bold part thereof is given which may need improvement. Alternatives are given at (1), (2) and (3) below, which may be a better option. In case, no improvement is needed, your answer is (4).
The man whom I thought was thoroughly honest proved to be a swindler.

Options

A. The man whom I thought was thoroughly honest proved a swindler
B. The man who I thought was thoroughly honest proved to be a swindler.
C. The man to whom I thought was thoroughly honest proved to be a swindler.
D. No improvement

Answer

D

Explanation

No improvement