Find out the correct sentence from the following options:

Concept

The noun “authority” meaning power or control to direct others takes the preposition “over”. The fixed collocation “to have authority over someone” expresses command or jurisdiction. Choosing the correct dependent preposition is what makes the sentence idiomatically correct.

Application

The sentence describes a mother’s power to direct her son, so “authority” must pair with “over”: “She has no authority over her son.” This is the grammatically and idiomatically correct form.

Why the other prepositions do not fit

• “authority upon her son”: “upon” denotes physical position or a point in time, not command over a person, so it is not the collocation used with “authority” in this sense.

• “authority for her son”: “for” signals purpose or benefit (acting on someone’s behalf), which changes the meaning away from control and is not idiomatic here.

• “authority of her son”: “of” would imply the son possesses or is the source of the authority, the opposite of the intended power exercised over him.