According to the passage, the risk of infection from airborne microorganisms would likely be greater during a ______.

A．bacteria can be most easily killed by removal of moisture
B．drying out a house will eliminate the risk of airborne infection
C．hot-Mr heating is better than steam heating because steam heating uses water
D．none of the above

A．spores are resistant to drying
B．the causative organism is encapsulated
C．droplets of sputum remain infective for a long time due to the resistance of the organisms to drying
D．none of these