Does sound tend to bend upward or downward when its speed is less near the ground?

Explanation:

When the speed of sound near the ground is reduced, (such as on a cold day when the layer of air nearest ground is colder than the air above) the higher speed of the wavefronts above cause a bending of sound toward the ground.

real, smaller and upside-down.   so the answer should be b.

come closer and become far apart and become steam/gas