4. For the current-mirror-loaded differential amplifier in Fig. 4. Assume β = 100, = 0.7 V, IVAI = 60 V, Vt = 0.7 V, and k(WI) = 2 mA/V2. Please find: (a) differential input resistance (5%), (b) Ad (5%), and (c) CMRR (5%).