Answer:
A) It will move at a different speed (i.e slower)
B) A vacuum
Explanation:
For A), Light moves at a different speed as it starts to interact more with the particles in said medium (in this case, water) than the earlier medium.
For B), Light propagates using its own particle, i.e the photon whereas sound is more of a transmission of energy from the particles it originates from. In a vacuum, there are no particles to transfer energy to, that is why light can travel in a vacuum and sound cannot