In which stage of the Law of Variable Proportions does total product reach its maximum and marginal product become zero?

1. In Stage 2 total product keeps rising at a diminishing rate until it reaches its maximum, where Stage 2 ends. 2. At that maximum point the marginal product of the variable factor is exactly zero. 3. So the answer is the end of Stage 2. 4. Stage 1 ends where AP is maximum (MP still positive), and Stage 3 has already-falling TP with negative MP, so neither matches MP being zero at TP's peak. _Source: ICAI BoS CA Foundation Paper 4 Business Economics, Ch 3 Unit I "Theory of Production", p.19_