Question

Which best describes what happens when light traveling through air enters water at an angle?

Answer 1

I think it is "A'' 'It moves along straight lines in air and changes direction when it enters water.

Answer 2

The correct choice is

A. It moves along straight lines in air and changes direction when it enters water.

This is because of phenomenon of refraction which  a ray of light experience when it moves from one medium to another medium. The light ray bends away  from the normal to the surface if it travels from denser to rarer medium. The light ray bends towards from the normal to the surface if it travels from rarer to denser medium.