Final answer:
Option (A), A solenoid valve is an electromagnet with a movable core that opens and closes a fluid passage.
Step-by-step explanation:
A solenoid valve is an electromagnet with a movable core that opens and closes a fluid passage. When an electric current passes through the solenoid coil, it creates a magnetic field that attracts the movable core, allowing fluid to flow through the valve. When the current is turned off, the core returns to its original position, closing the valve and stopping the fluid flow.
An example of a solenoid valve is a water flow control valve in a washing machine. When the washing machine is turned on, an electric current activates the solenoid valve, allowing water to flow into the machine. When the washing machine is turned off, the solenoid valve is deactivated, closing the valve and stopping the water flow.