Question

Choose the option that best fills in the blank:
_____ does not know which course is best.

• A. none
• B. one
• C. they
• D. all

Answer 1

The correct option is B one

An indefinite pronoun is a pronoun that refers to non-specific beings, objects, or places.

In the given sentence the pronoun must be a singular pronoun as the verb used is a singular verb.

Thus we can eliminate options C and D as incorrect as they are in the plural form.

The indefinite pronoun 'one' must be used as it is singular and positive. Thus option B is the correct answer.

We cannot use 'none' as the negative 'not' has already been used in the sentence.

Thus option A is also incorrect.