A dynamo converts:
A. Electrical energy into mechanical energy
B. Electrical energy into heat energy
C. Mechanical energy into electrical energy
D. Heat energy into electrical energy

Hint – A dynamo is a device or generator which is used for converting mechanical energy into electrical.

Complete step-by-step answer:
We have been asked about the dynamo.
So, a dynamo converts mechanical energy into electrical energy.
It used rotating coils of wire and magnetic fields to convert mechanical rotations into a pulsing direct electric current.
Dynamos were the first electrical generators which are capable of delivering power for industries, and many other electric-power conversion devices were based upon the principle of dynamo.
Hence, the correct option is C.

Note – The dynamos lay the foundation upon which many other electric-power conversion devices were based, many of the devices like electric moto, the alternator and the rotary converter. As mentioned in the solution the dynamos are the generators which convert mechanical energy into electrical energy.