Which would constitute the last step in a central-fan cooling control sequence?

A. During the cooling season, when the home's air temperature rises above a predefined setpoint, the room thermostat calls for cooling and energizes the refrigeration control circuit
B. Cool air from the fan system is delivered through ductwork to occupied spaces within the home. When the space temperature within the fan unit drops below the room temperature setpoint, the refrigeration unit shuts down.
C. When the air temperature within the fan unit drops below the setpoint of an internal controller, the blower motor is energized.
D. The blower continues to operate until the temperature within the fan unit rises above the setpoint of the internal controller, at which time the blower shuts off.