Step 1: Understanding the Correct Preposition
The correct preposition here is "between," as it is used when referring to two people or things. The sentence talks about "Hari" and "Prakash," who are two people, so "between" is the most suitable choice.
Step 2: Evaluating the Other Options
- "Among" (Option B) is used when talking about more than two things or people, which is not the case here.
- "Besides" (Option A) means "in addition to" and does not fit the context of positioning two people.
- "Beyond" (Option C) indicates a position further away, which is not appropriate here as the sentence focuses on the relative position between two people.
Step 3: Conclusion
Thus, the correct preposition is "between," making the sentence: "I sat down between Hari and Prakash."