In a young's double slit experiment two films of same thickness 't' but of different refractive indices $\mu_1$ and $\mu_2$ are placed in front of slit A and B respectively. If $( \mu_1 > \mu_2)$ the central maxima will

Question

(a) shift towards A

(b) will shift toward B

(c) will not shift at all

(d) no pattern will be obtained