A MOS differential amplifier is driven with an input CM level of 1.6 V. If I S S (biasing current source) is 0.5 mA, Vt = 0.5 V, and VDD = 1.8 V, what is the maximum allowable load resistance (RD)? Hint: What is required for the transistors to be in saturation? 3.5 KOhm 2.8 KOhm 1.0 KOhm 7.50 KOhm