Which condition determines the threshold point for a MOS Capacitor?

Correct option is C

The threshold point (or strong inversion point) of a MOS capacitor is reached when the surface potential of the semiconductor allows the concentration of minority carriers at the surface to become equal to the concentration of majority carriers in the bulk (the bulk doping concentration). For a p-type substrate, this means the electron concentration at the surface equals the acceptor doping concentration ($$N_{A}$$​) in the bulk. This condition marks the onset of the inversion layer, where a conductive channel forms, enabling the device to operate as a transistor.