Which of the processes listed would be the most satisfactory method to use to lower the humidity of the air being circulated by an air conditioning system?

Correct Answer: Option B — Cooling the air to a point below dew point, and then reheating it.

Dehumidification is achieved by cooling air below its dew point to condense moisture out of the air stream. Because this process also lowers the air temperature significantly, the air must be reheated to a comfortable discharge temperature, effectively reducing the absolute humidity while maintaining the desired space temperature.