7. Which of the following statements describes CORRECTLY about cool and warm air?
I. Cool air is denser than warm air.
II. Cool air's density is the same with the density of warm air.
III. Cool air is denser than warm air thus it sinks on the ground.
VI. Warm air is less dense than cool air thus it will rise in the atmosphere.
A. I, II and III only
B. I, III, and IV only
C. II, III and IV only
D. II, III and IV only​