Concept:An LED (light-emitting diode) is a component that lights up when electric current flows through it.Explanation:An LED is a semiconductor device that emits light when current passes through it in the forward direction.In a circuit, a glowing LED clearly shows that current is flowing.A capacitor stores electrical energy, and a diode only allows current in one direction without showing its flow.The word “indicator” is a general name, but the actual specific electronic component used for this purpose is the LED.Answer:C. LED.