Choose the correct option by making hypothesis based on given assertion and reason

Choose the correct option by making hypothesis based on given assertion and reason. Give an explanation.
a) Both A and R are true and R is the correct explanation of A.
b) Both A and R are true and R is not the correct explanation of A.
c) A is true but R is false.
d) Both A and R are false.
e) A is false but R is true.

Assertion (A) : The refractive index of a prism depends only on the kind of glass of which it is made of and the colour of light.
Reason ® : The refractive index of a prism depends on the refracting angle of the prism and the angle of minimum deviation.

b) Both A and R are true and R is not the correct explanation of A.