Insert proper preposition in the sentence. I prevailed ______ him to join our group.

Correct answer: upon

Explanation: ✅ Correct Answer: B) upon 📚 Explanation: The verb 'prevail' is traditionally followed by the preposition 'upon' when it means to successfully persuade or convince someone to do something. It shows that the person was encouraged to take a specific action. Using 'upon' completes the formal idiomatic expression required for this sentence. It clarifies the relationship between the speaker's persuasion and the friend's decision to join the group.