When a person speaks, sound waves leave through the person’s mouth and spread out in many directions. Which row states the physical process that causes the sound waves to spread out and the reason why this happens as the sound waves leave an open mouth?

	process	reason
A	diffraction	sound wavelengths are small compared to the size of the mouth
B	diffraction	sound wavelengths are large compared to the size of the mouth
C	refraction	sound wavelengths are small compared to the size of the mouth
D	refraction	sound wavelengths are large compared to the size of the mouth