If a ray is incident on an interface from a high refractive index material to a

If a ray is incident on an interface from a high refractive index material to a low refractive index material, at the critical angle, which of the following statements are true? (Check all that apply) 

a. The angle of refraction is 90 degrees to the normal 
b. There is no transmission 
c. There is total internal reflection 
d. The angle of reflection is 90 degrees to the normal 
e. There is no reflection, only refraction