The unity gain frequency of a MOSFET is dependent on(i) The parasitic capacitance between the gate and the source(ii) The parasitic capacitance between the gate and the drain(iii) The transconductance of the MOSFET(iv) The load resistancea.(ii) and (iv) onlyb.(i) and (iv) onlyc.(iv) onlyd.(i), (ii) and (iii) onlye.(iii) only

The unity gain frequency, also known as the gain bandwidth product for a MOSFET, is dependent on the transconductance of the MOSFET and the parasitic capacitances.

(i) The parasitic capacitance between the gate and the source (Cgs) - This capacitance plays a role in determining the frequency response of the MOSFET. It affects the speed at which the MOSFET can operate, and hence, the unity gain frequency.

(ii) The parasitic capacitance between the gate and the drain (Cgd) - This capacitance, also known as the Miller capacitance, also affects the frequency response of the MOSFET. It is usually the dominant capacitance in determining the unity gain frequency.

(iii) The transconductance of the MOSFET (gm) - The transconductance, which is the ratio of the change in the output current to the small change in the input voltage, also affects the unity gain frequency. The higher the transconductance, the higher the unity gain frequency.

(iv) The load resistance - The load resistance does not directly affect the unity gain frequency. It can affect the overall gain of the amplifier, but not the frequency at which the gain becomes unity.

So, the correct answer is (d) (i), (ii) and (iii) only.