To raise a bucket of water from a well, you could tie a rope to cylinder that can be rotated with a crank having an larger radius than that of the cylinder; in other words, you could have used a(n):

wheel and axle system

Explanation:

The wheel is block of material that is circular in shape and generally has a hole in the center through which a rod is pushed through which is called the axle. It is one of the most commons types of assembly's used in everyday life.

In order to lift water from the well although it is possible to lift without using the wheel axle assembly it is easier to lift water with the assembly.

Hence, the question here is referring to wheel and axle system.

where's the