The main purpose of the passage is to______.A．introduce the dangers of air－conditioningB．e

The main purpose of the passage is to______.

A．introduce the dangers of air-conditioning

B．explain the defects of old air-conditioning

C．illustrate how air-conditioning affects people"s health

D．advocate abandoning old air-conditioning

请帮忙给出正确答案和分析，谢谢！