General exam question G6A09

WhyIn a MOSFET, the gate is separated from the channel by a thin insulating layer. A MOSFET's gate electrode sits above the channel but is electrically isolated from it by a thin layer of insulating oxide, which is exactly what the name metal-oxide-semiconductor field-effect transistor describes, answer B. The gate isn't formed by a back-biased junction (that describes a JFET instead), and it's the gate that's insulated from the channel, not the source from the drain or a metal-deposited source, so A, C, and D misdescribe MOSFET construction.