Final answer:
The correct component to prevent liquid flood-back in a heat pump with a reciprocating compressor is a suction accumulator, which stores excess liquid refrigerant to prevent it from entering and damaging the compressor.
Step-by-step explanation:
To prevent liquid flood-back which can damage the compressor in a heat pump system, several components can be installed. Of the options provided, the correct component to prevent liquid refrigerant from returning to the reciprocating compressor is a suction accumulator. A suction accumulator stores excess liquid refrigerant to prevent it from entering the compressor and causing damage. It is especially useful during transient conditions where the chances of liquid flood-back are high. Other components mentioned such as the crankcase heater, liquid line filter-drier, and thermostatic expansion valve serve different purposes. The crankcase heater prevents refrigerant from migrating and condensing in the oil within the compressor when it's not running; the filter-drier removes moisture and contaminants from the refrigerant, and the expansion valve regulates the flow of refrigerant into the evaporator.