GKFix MCQ Question

In the formula n21 = sin[(A + Dm)/2] / sin(A/2), what do the symbols A and Dm represent?

• A. A is the angle of incidence, Dm is the angle of deviation
• B. A is the angle of refraction, Dm is the maximum deviation
• C. A is the angle of emergence, Dm is the angle of incidence
• D. A is the angle of the prism, Dm is the angle of minimum deviation