Select the most appropriate option to fill in the blank

Select the most appropriate option to fill in the blank.

Knowledge of all the border countries______required to apply for the job of merchant.

A.            Were

B.            Are

C.            Was

D.            Had

Sol:

Option c ‘was’ is the correct word to fill the blank, when a sentence has more than one subjects connecting with ‘of’ the subject before ‘of’ is the real subject of the sentence and we use helping verb according to it, the subject of the sentence is ‘knowledge’ and not ‘countries’ so a singular verb is required.