Which one among the following pairs of ions cannot be separated by `H_2S` in dilute HCl ?

Options

A. `Al^(3+), Cu^(2+)`
B. `Zn^(2+), Cu^(2+) `
C. `Ni^(2+), Pb^(2+) `
D. `Sn^(4+),Bi^(3+)`

Answer

D

Explanation

Both belong to group II .