Correct statement

This question tests the correct usage of prepositions with the verb “insist.”

• Correct Option: B) He insisted on doing that. The verb “insist” is typically followed by the preposition “on” when it means to demand something forcefully or to persist in a particular action, especially when followed by a gerund (the -ing form of a verb).
• Distractor A) He insisted to do that. This construction is grammatically incorrect. “Insist” is not followed by an infinitive (to do) in this context.
• Distractor C) He insisted for doing that. The preposition “for” is incorrect here.
• Distractor D) He insisted at doing that. The preposition “at” is also incorrect in this idiomatic expression.

Mastering phrasal verbs and prepositional phrases is key to accurate English grammar.