What three things must an electric circuit contain?

• A. Source of electrical energy, a load, and conductors to join the source and the load.
• B. A battery, a resistor, and a capacitor.
• C. A switch, a fuse, and a transformer.
• D. A source, a display, and a case.

Answer: (A)

An electric circuit must form a complete loop that allows current to flow: a source of electrical energy provides the voltage, a load uses that energy to do work, and conductors provide the path that connects the source to the load. This three-part structure is what the option describing a source, a load, and conductors to join them captures. The other options describe specific components that aren’t required in every circuit: a particular trio of parts like a battery, resistor, and capacitor is just one possible arrangement; protective or control devices such as a switch, fuse, and transformer aren’t mandatory for a basic circuit; and a display and case aren’t fundamental circuit elements. The essential concept is a complete loop with energy source, a device that uses energy, and a conducting path.