Concept:Prime cost is the sum of direct materials, direct labour, and direct expenses.
Explanation:Direct labour cost is a direct cost because it is used directly in production.
Hiring a machine for production is a direct expense, so it also forms part of prime cost.
Factory overheads are indirect production costs, not part of prime cost.
Warehouse rent is an administrative or selling expense, not a direct production cost.
Thus, the expenses that constitute prime cost are direct labour cost and hiring of machine for production only.
Answer:B. I and III only