Answer:
Explanation:
Sciguy gave you a good explanation of what you have to do.
I'm only adding this so you can award a Brainliest.
The normal is a line that is vertical to the surface of the mirror. That makes the two angles that make up the division by the ray a set of 2 complementary angles. It is the angle between the normal and the ray the critical angle. The two angles much be equal.
A does not work. The critical angles are 40 and 50 which is not the way reflection works.
B has an extra step. You need to be talking about the complement of the incoming ray. The angle with the normal on the left is not the same as the angle and on the right.
C has the same basic problem. The outgoing ray with make a 50 degree angle with the normal. They are not equal.
D is the only possible answer. The compliment of 50 is 40 which makes the angle on the right = to the angle on the left.
