Final answer:
In a heat pump system, during the cooling cycle, the indoor coil acts as the evaporator. In contrast, during the heating cycle, the outdoor coil functions as the evaporator. The correct option is b. Outdoor/Indoor.
Step-by-step explanation:
The operation of a heat pump system involves a cycle that can be reversed for either heating or cooling a space. During the cooling cycle, the indoor coil acts as the evaporator where the refrigerant absorbs heat from the indoor air, thereby cooling the space. On the other hand, in the heating cycle, the outdoor coil serves as the evaporator, absorbing heat from the outdoor air to heat the space. In this cycle, the refrigerant absorbs heat at the outdoor evaporator, and this energy is transferred indoors where it is released into the space as the refrigerant condenses at the indoor condenser.
Therefore, for the question asked, during the cooling cycle, the indoor coil acts as the evaporator, and during the heating cycle, the outdoor coil acts as the evaporator. The correct option for both scenarios is: b. Outdoor/Indoor.