The correct statement about the effect of temperature on the speed of sound is:
As temperature increases, the speed of sound increases because molecules in the medium collide more frequently.
As temperature rises, the kinetic energy of molecules increases, leading to more frequent and energetic collisions, which facilitates the transmission of sound waves, resulting in an increased speed of sound. However, it should be noted that while the density of a medium may change with temperature, the primary reason for the increase in the speed of sound with temperature is the increase in the kinetic energy of the molecules, not simply the change in density.