Right choice is (a) True
Explanation: Yes, Modulus method can be used for determining height and diameter of the riser. In this method, we find modulus of casting and riser which is the ratio of volume and area. The ratio of modulus of the riser to that of casting is 1.2, and the ratio of riser height to its diameter is 1.5. By using these two equations dimension of the riser is estimated.