Answer:
C. A ray incident parallel to the axis refracts so that it passes through the focus on the right hand side
Step-by-step explanation:
The third ray is the blue ray in the following figure
Therefore, the third ray is a ray parallel to the axis that refracts and passes through the focus of the right side.
So, the answer is:
C. A ray incident parallel to the axis refracts so that it passes through the focus on the right hand side