Consider a glass cube slab of dielectric bound by the planes x = 0, x = a; y = 0, y = b; z = 0, z = c; with b > a > c. The slab is placed in air and has a refractive index of n. The minimum value for n such that all rays entering the dielectric at y = 0 reach y = b is
(A) 1
(B) √2
(C) √3
(D) 2
