The correct answer is option-3: Light Emitting Diode.

An LED, also known as a Light Emitting Diode, is a semiconductor device that emits light when an electric current passes through it. It consists of a semiconductor material that emits light when electrons move through it, releasing energy in the form of light.

Option-1, Licence for Energy Detector, is not the correct explanation for LED. LED does not stand for any license relating to energy detection, so this option is incorrect.

Option-2, Light Energy Device, is not the correct explanation for LED. While an LED does produce light energy, the term "Light Energy Device" is not commonly used to refer to LEDs. Therefore, this option is incorrect.

Option-4, Lost Energy Detector, is not the correct explanation for LED. LEDs are not used for the purpose of detecting lost energy. This option is incorrect.

In conclusion, LED stands for Light Emitting Diode, which is a semiconductor device that emits light when an electric current is passed through it.