Correct option is C
When a positive voltage is applied to the gate terminal of a MOS capacitor (typically with a p-type semiconductor substrate), an electric field is created across the oxide layer.
The positive voltage at the gate creates a positive charge on the metal side of the capacitor, which generates an electric field directed into the semiconductor.
Holes are positively charged charge carriers (majority carriers in a p-type substrate).
Since like charges repel each other, the positive electric field from the gate electrode exerts a repulsive force on the positively charged holes, pushing them away from the oxide-semiconductor interface and deeper into the substrate.
This repulsion of holes creates a region near the surface that is depleted of free charge carriers, called the depletion region, which then eventually leads to the formation of an inversion layer of electrons if the voltage is high enough.
