(a) a force multiplier
(b) a speed multiplier
(c) a device to change the direction of effort
(d) an energy multiplier

Solution –

The correct option is (a).

As a force multiplier, a movable pulley is employed.
Explanation: The movable pulley has a mechanical advantage greater than 1. As a result, the weight can be lifted with a single moveable pulley by exerting an effort equal to half the load, i.e. the single movable pulley functions as a force multiplier.