The wine glass

How can the light phenomenon on the book be explained?

a) The water in the glass intensifies the light source. So the light, which passes through the water, looks brighter on the book.

b) The rays of light are refracted (by water) at the boundaries between air and glass. Thereby the rays of light are deflected onto a smaller area which is brighter consquently.

c) The rays of light are constantly deflected inwards while passing through the water. So the light is moving on a bend and collecting in a smaller area.