Traditionally, which of the listed refrigerants has been more suitable than the others for use in a centrifugal refrigeration compressor?

Correct Answer: Option A — R-11

Centrifugal compressors require large volumetric displacement and low operating pressures, properties historically inherent to R-11. Under marine HVAC standards, low-pressure refrigerants match the high-volume, low-compression-ratio demands of centrifugal impellers efficiently.