it will be option "a"
Refractive index B wrt A = nBA = V1/V2 = Speed of light in medium A / speed of light in medium B
Since ray of light bends towards the normal, when it goes from medium A to medium B, therefore, medium A is rarer and medium B is denser, speed in rarer medium (v1) is greater than the speed of light in denser medium (v2) ,so V1 > V2(improper fraction), hence nBA > 1
n21 greater then 1
then optical density M1 is rarer (A),
M2 is denser.
then bending of ray towards the normal
Conclusion :- Greater the value of RI more is bending towards normal