'A' and 'C' both show that behavior.
'D' also shows it, but the object is moving backwards when time begins.
First it moves faster and faster backwards, then it moves slower and slower backwards.
The density of ice is less than the density of water. C
Answer
D.Diffraction
Explanation
Diffraction is a property that is experienced by waves when they come across a barrier when they are in motion.
The ways tends to curve behind the barrier. This is called diffraction of waves.
Now, sound is a wave and it also experience diffraction. . So the brother will be able to hear the sound due to diffraction
The longer you continue to listen, the more beats will be heard.
They'll occur at the rate of (260Hz - 254Hz) = 6 Hz .