If total internal reflection is to occur, what must be incident angle be relative to the critical angle?

a) It must be larger than or equal to the critical angle.
b) It must be smaller than or equal to the critical angle.
c) It must be equal to the critical angle.
d) It must be smaller than the critical angle.
e) Total internal reflection only depends on the indices of refraction of the two materials, so it doesn’t matter what the incident angle is.