Final answer:
The capillary tube, when functioning as both the liquid line and metering device, connects between the evaporator and the b) condenser in an air conditioning system.
Step-by-step explanation:
When the capillary tube serves the function of both the liquid line and the metering device, it is connected between the evaporator and the b) condenser.
The capillary tube acts as an expansion device where it reduces the pressure of the liquid refrigerant allowing it to expand and cool before it enters the evaporator. In an air conditioning system, the condenser is the component that converts gas into a liquid by cooling it down. The high-pressure gas from the compressor enters the condenser, where it releases its heat to the surroundings and condenses into a high-pressure liquid. This liquid then moves through the capillary tube, experiencing a pressure drop and temperature decrease, before it reaches the evaporator to absorb heat and start the cycle again.