What defines a semiconductor?

A semiconductor is defined as a material that can conduct electricity under certain conditions, which is captured accurately in the correct option. This unique property is crucial in the realm of electronics because it allows semiconductors to act as both conductors and insulators depending on various factors such as temperature, impurities (doping), and the presence of electric fields.

Semiconductors have a band gap that makes them capable of conducting electricity at room temperature when sufficient energy is supplied, which is different from conductors that allow free flow of electrons all the time. By manipulating these properties through various forms of doping or applying voltage, semiconductors can be turned on or off, making them essential for devices like transistors, diodes, and integrated circuits.

Understanding semiconductors is fundamental to modern electronics as they serve as the building blocks for most electronic devices, including computers, smartphones, and solar cells.