The Index Profile of a Core of Multimode Graded Index

The index profile of a core of multimode graded index fiber is given by-

A) n (r) = n1 [1 - 2?(r2/a) 2]1/2; rB) n (r) = n1 [3 - 2?(r2/a) 2]1/2; rC) n (r) = n1 [5 - 2?(r2/a) 2]1/2; r>a
D) n (r) = n1 [1 - 2?(r2/a) 2]1/2; r