Which of the following description about sending back to send air is correct?
A . The air outlet is located in the upper part of the air-conditioned room and the air return is located in the lower part of the air-conditioned room
B . Air flow from the central outlet sent through the work area and then discharged from the lower air outlet
C . Air flow from the upper outlet sent out into the work area and then discharged from the upper air outlet to form on the back to send the air flow organization
D . No need to control the entire space as a control object, only the air conditioning area located in the lower part of the room to control
Answer: A