Below is a diagram used when a student submitted their lab writeup of the refraction investigation. When performing the investigation using the dish of liquid, the students compared two angles, the angle of incidence and the angle of refraction. It turns out you can measure these angles different ways. Only one of the choices listed below lists a correct pair of angles to measure and compare. (In other words, which pair could be an angle of incidence and an angle of refraction for the shown picture). Which pair is it?

a. Angles 1 and 2
b. Angles 1 and 4
c. Angles 1 and 3
d. Angles 2 and 4