The correct answer to the question is : Light or any electromagnetic wave.
EXPLANATION :
Before going to answer this question, first we have to understand refraction.
Refraction is the optical phenomenon in which light ray will bend at the interface of the two media having different optical densities.
When light ray comes from optical rarer medium to optical denser medium, the ray will bend towards the normal. It is so because the velocity of light in rarer medium is more than velocity of light in denser medium.
When the light comes from optical denser medium to optical rarer medium, the light ray bends away from the normal. It is so because the velocity of light increases in the rarer medium.
As per the question, wave is moving from air to ocean, and its velocity slows down.
Hence, there is refraction. So, the wave must be light or any electromagnetic wave.
