Question

Plz help!!!!!!
On cloudless winter nights, the sound from a distant sound source is sometimes heard more clearly than during the day time.
Q: Given the condition above, from 1-4 below choose the answer that correctly indicates the relationship between air temperature in the upper sky (T.h) and air temperature near the ground (T.g), and between the speed of sound in the upper sky (V.h) and speed of sound near the ground (V.g).
1/ T.hV.g3/ T.h>T.g, V.hT.g, V.h>V.g

Answer 1

http://www.acs.psu.edu/drussell/Demos/refract/refract.html