Answer:
A. velocity and wavelength
Step-by-step explanation:
When a wave travels from one medium to another it undergoes refraction which results to the change in direction.
Refraction of a wave is one of the property of waves that occurs when a wave changes direction when it passes from one medium to another. This occurs as a result of bending of the wave which occurs since the mediums involved are of different density and refractive index.
Apart from the change in direction, refraction is accompanied by the change in wavelength of a wave and thus a change in speed.