A heat pump is used to heat a room where the outside temperature is -10°C. If the heat pump requires a power input of 2 kW, and the room requires a heat input of 15 kW to maintain the temperature at 25°C, (a) find the COP of the heat pump. (b) Determine if the heat pump is reversible, irreversible, or impossible. (c) If 20 kW of heat input was required to maintain the temperature of the room instead, would your answer to part (b) change?