Subscribe TechModgy to learn about new technologies!

In each of these questions, a sentence has been divided into four parts and marked a. b, c and d. One of these parts contains a mistake in grammar Idiom or syntax. Identify that part and mark it as the answer.

A. Though he claimed he knew French,

B. I was sure that he only could follow it

C. but could not either write

D. or speak it with fluency

Please do not use chat terms. Example: avoid using "grt" instead of "great".