Disregarding friction, what is the mechanical advantage of a twofold purchase when rove to disadvantage?

Correct Answer: Option C — 4

A twofold purchase utilizes two blocks with two sheaves each. Roving to disadvantage means the hauling part leads away from the load. With four parts of the line supporting the weight, the mechanical advantage is four. This configuration provides a four-to-one ratio for lifting, disregarding internal friction losses.