✓ Correct answer: C
MWR weights periods by capital invested. A large contribution before poor performance drags MWR below TWR — more capital absorbed the loss.
✗ Why the others are wrong
A. Contributions before poor returns reduce — not raise — MWR relative to TWR.
⚠ Common trap
Confusing cash-flow timing with compound return. MWR ≠ TWR whenever external flows occur.