A reed switch is best described as?

A reed switch is accurately described as a magnetic switch with two contacts. These switches consist of two ferromagnetic reeds that are sealed within a glass tube, and they operate based on the presence of a magnetic field. When a magnet is brought close to the switch, the reeds are magnetized and come together, completing the electrical circuit and allowing current to flow. This mechanism makes reed switches effective in applications where non-mechanical activation is preferred, such as in security systems and various sensing applications.

The other descriptions do not accurately represent how reed switches function. A reed switch does not require mechanical pressure to activate, nor does it utilize light for detection. Additionally, while reed switches can handle moderate power applications, they are generally not designed for high-power circuits, making option C the most fitting choice among the alternatives presented.