Select the most appropriate choice to fill in the blank.
The local bank was robbed by a group of men, _________________ were armed.

Correct option is A

The phrase that can be filled in the blank is ‘four of whom’ to make the sentence grammatically and contextually correct. • Four of whom refers back to the group of men and indicates a specific subset of them that were armed. Grammatical Rule involved: Relative pronoun usage - To introduce a relative clause referring back to a group mentioned earlier. • In this context, ‘four of whom’ clearly connects the armed men back to the earlier noun.
Meanings of other given words:
• Four of these - incorrect pronoun reference. • Four of those - ambiguous and less precise. • Four whom - grammatically incorrect. • Therefore, only ‘four of whom’ works in this context.