how does the power switch on a computer work?

a. Turning the switch on causes the conductors to release electrons.
b. Turning the switch on activates the power source to allow electrons to flow.
c. Turning the switch on turns on the parts that convert electrical energy to other forms.
d. Turning the switch on completes the circuit between the power source and the load.

d. Turning the switch on completes the circuit between the power source and the load.