The correct answer is: C. Rs. 70000
Prime cost is the direct cost of producing a product. It includes the cost of materials and labor used in production. In this case, the prime cost is Rs. 70000, which is calculated as follows:
Prime cost = Materials + Labour cost
= Rs. 35000 + Rs. 25000
= Rs. 70000
The other options are incorrect because they do not include the cost of materials.