The correct answer is:
(b) Metal oxide semiconductor field effect transistor
Explanation:
MOSFET stands for Metal Oxide Semiconductor Field Effect Transistor. It is a type of field-effect transistor (FET) used for switching and amplifying electronic signals in various electronic devices. The structure of a MOSFET includes a metal gate, an oxide layer (usually silicon dioxide), and a semiconductor material (typically silicon), which is where the channel forms for the current to flow when the transistor is activated.
Thus, the correct expansion of MOSFET is Metal Oxide Semiconductor Field Effect Transistor, as given in option (b).