What is a simple device that opens and closes an electrical unit called?

The switch is the simple device that opens and closes an electrical unit.

An Ampere is the SI unit used to measure the flow of current across the surface at the rate of one coulomb per second. The ampere is used to measure electricity.

Option A is also wrong because a volt is used as a unit of electrical pressure which causes current to flow in a circuit.

Option B is wrong because a discharge is when the electrical energy from a charged body is removed such as batteries or capacitor.

A device that open and closes an electric u it is called switch