In general, how does temperature of a medium affect the speed of sound through that medium?

Molecules at higher temperatures have more energy, thus they can vibrate faster. Since the molecules vibrate faster, sound waves can travel more quickly through a medium. Sound travels faster in warmer temperatures than cooler and more slowly in cooler temperatures.

your answer is c! hope this : )

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.