A simple machine is a device that helps us do work more easily.

In physics, work is done when a force moves an object through a distance:

$$W = F \times d$$

A simple machine does not reduce the total amount of work needed ideally, but it can make the work easier by:

1. reducing the force needed,
2. changing the direction of the force, or
3. increasing the distance over which the force is applied.

Examples of simple machines include:

• lever
• pulley
• inclined plane
• wheel and axle
• screw
• wedge

Now check each option:

A) that can provide electric current

This describes something like a battery or generator, not a simple machine.

B) which can only carry people from one place to another

This describes a transport device, not a simple machine.

C) with which work can be done easily

This matches the definition of a simple machine. A simple machine helps make work easier.

D) which changes the state of rest or of uniform motion of an object along a straight line

This describes the effect of a force, according to Newton’s first law, not the definition of a simple machine.

Therefore, the correct answer is:

C) with which work can be done easily