Of whom can refer to people in a non-defining clause.
Of which can refer to objects in a non-defining clause.
A quantifier can come before of whom or of which.
Of which is required whenever the antecedent is plural, including people.✓Ճիշտ պատասխան
Բացատրություն
Plural number does not decide between whom and which; the human or nonhuman nature of the antecedent does. People take whom in this structure, whereas objects and other things take which.