Complete the following sentence by using a suitable question tag :

Few students knew the solution, ________.

Did they ?

The correct question tag is: Did they?

In English grammar, a question tag is a short question added to the end of a statement to turn it into a question and to invite confirmation or agreement. The main statement "Few students knew the solution" has a negative connotation because of "few." In such cases with negative or semi-negative words like "few," "little," "hardly," etc., the question tag is positive.

So, we use "Did they?" to confirm that only a few students knew the solution.