How far is the second floor window from the ground

A．breathing smoke is net good for one's health
B．smoke will enter the room by an open window
C．it is difficult for fresh air to reach the second floor
D．it is better to keep your head low when there is smoke in the room

A．the only way of escaping a fire
B．the best place if you want to get out
C．one of the possible ways to escape a fire
D．safer than any other ways of escaping a fire