High suction pressure accompanied by low suction temperature to a refrigeration system compressor is caused by which of the following?

Correct Answer: Option C — the expansion valve being open too wide

An expansion valve open too wide overfeeds the evaporator with liquid refrigerant, preventing complete vaporization prior to the suction line. This floods the evaporator, resulting in high suction pressure from excessive boiling volume and low suction temperature due to unevaporated liquid entering the stream.