Final answer:
A battery produces DC and a generator produces AC.
Step-by-step explanation:
The statement that is true is a) a battery produces dc and a generator produces ac.
A battery generates direct current (DC) voltage, which is unidirectional. This means that the current flows in only one direction. On the other hand, a generator produces alternating current (AC) voltage, where the current periodically reverses direction.
For example, most household appliances need AC voltage, which is provided by a generator. However, devices like computers, cell phones, flashlights, and cars use DC, and they are powered by batteries.