As the amplitude of a sound wave in air decreases to zero, ________________.
(a) Nothing happens to the condensations and rarefactions of the wave
(b) The condensations and rarefactions of the wave occupy more and more distance along the direction in which the wave is traveling
(c) The condensations of the wave disappear, but nothing happens to the rarefactions
(d) Nothing happens to the condensations of the wave, but the rarefactions disappear
(e) Both the condensations and the rarefactions of the wave disappear