The answer is, “Light
waves always travel the same speed; however, the speed of sound is determined
by the medium that it travels through.”
The light of speed is
constant because “Speed is equal to distance divided by time”. In order to keep the speed of light constant,
“time and space will both become distorted to accommodate it”.
The other options given are
wrong. Sound waves do vary according to
the temperature and Light waves cannot travel fast in tightly packed
solids.