Which of the conditions listed could cause excessively low refrigerant pressure at the compressor suction of a TXV controlled refrigeration system?

Correct Answer: Option C — The system is low on refrigerant.

A shortage of refrigerant reduces the mass flow rate entering the evaporator via the thermal expansion valve. This starves the cooling coil, causing rapid vaporization early in the circuit and a significantly lower boiling point pressure at the compressor suction.