CONCEPT:Complementary Metal-oxide-semiconductor (CMOS) uses complementary & symmetrical pair of P-type & n-type MOSFETS. The two important characteristics of CMOS devices are high noise immunity and low power DISSIPATION.In CMOS, during static operation at a TIME, only one MOS is ON i.e. either PMOS or NMOS. So there is no direct path from the power supply to the ground. Hence, Power dissipation in CMOS is low in static operation but it has high power dissipation in DYNAMIC operation.Calculation:As the given figure is of CMOS with two inputs.The upper part is PMOS which is switched on when 0 is applied and NMOS is switched on when 1 is applied. Fig A Fig B1. When S = 0 is applied, the PMOS connected to S (upper one) will be shorted and P at PMOS will appear across the output in complemented form as shown in fig(A).So Output = P̅2. Now when S = 1 is applied, the NMOS connected to S (lower one) will be shorted, and due to which ground will appear across the output and the circuit will go in a high impedance state as shown in fig(B).Hence option (2) is the correct answer.