Question

To convert mechanical energy into electrical energy, one can use

(a) DC dynamo
(b) AC dynamo
(c) motor
(d) transformer

Answer 1

(a) DC dynamo
(b) AC dynamo

An AC or DC dynamo can be used to convert mechanical energy to electrical energy.
A motor converts electrical energy to mechanical energy and a transformer is used to step up or down the voltage or simply to transfer electrical energy.