- Step 1: Valid teams: (A, C), (B, D) or (A, D), (B, C).
- Step 2: If C with A: Select (A, C), (B, D).
- Step 3: Other team = B, D.
- Step 4: Verify: Satisfies A and B not together, C and D not together.
- Step 5: Check options: Option (2) is B and D, which matches.
- Step 6: Ensure no other valid pairing conflicts.