A piece of n-type semiconductor is sunjected to an electric E. The left end of the semiconductor is exposed to a radiation so that electron-hole pairs

A piece of n-type semiconductor is sunjected to an electric E. The left end of the semiconductor is exposed to a radiation so that electron-hole pairs are generated continuously. Let n be the number density of electron. The electron current density `J_(e)` is given `J_(e)=enmu_(e)E_(x)+eD_(e)(dn)/(dx)` . The dimensions of electron drift mobility `(mu_(e))` . and electron diffusion coefficient `(D_(e))` are respectively
A. `[M^(-1)T^(2)]and [L^(2)T^(1)]`
B. `[M^(1)T^(2)I^(-1)] and [M^(1)L^(2)T^(1)]`
C. `[M^(-1)T^(2)I^(1)] and [L^(2)T^(1)]`
D. `[M^(-1)T^(2)I^(2)] and [L^(1)T^(-2)I^(1)]`