Complete the sentence using the correct option:-

My grandfather was a clever man, he _____ speak five languages.

A. Can
B. Cannot
C. Could
D. Could not
E. May

Choose the correct answer from the options given below:

C only

The correct answer is Option (3) → C only

The completed sentence would be: "My grandfather was a clever man, he could speak five languages." This indicates that in the past, he had the ability to speak five languages.