Which statement correctly describes how the speed of sound in air changes as the air temperature increases from 0 °C to 25 °C, with all other conditions held constant?
(a) It decreases, because warmer air has lower density.
(b) It remains essentially constant, because the speed of sound in air is about 343ms−1 regardless of temperature.
(c) It increases.
(d) It doubles, because the speed of sound is directly proportional to temperature.