Step 1: Understanding the Question:
We need four correct pairs. A good way is to start with the pairs that we are most sure of, and use them to cut options.
Step 2: Start with the easiest pair.
The word IPKF belongs only to Sri Lanka, because the force went there in 1987. So (B) matches (IV). Option 1 pairs (B) with (II) and option 3 pairs (B) with (I), so both are out. Only options 2 and 4 have B-IV.
Step 3: Use a second sure pair.
The exchange of enclaves is a land boundary matter. It concerns Bangladesh, which has a long land border with India. So (D) matches (II). Option 2 has (D) with (III), so it is out.
Step 4: Check what is left in option 4.
Option 4 says A-III and C-I. The Seven Party Alliance was the group of Nepali parties in 2006, so Nepal matches (III). The mercenary coup of 1988 hit the Maldives, so (C) matches (I).
Step 5: Confirm with elimination.
All four pairs in option 4 hold, and this matches the facts for each country.
Step 6: Write the answer.
The matching is A-III, B-IV, C-I, D-II.
Final Answer:
Using IPKF for Sri Lanka and enclaves for Bangladesh leaves only option 4.
\[ \boxed{\text{Option 4}} \]