Which one of the following pairs of ions canot be separated by `H_(2)S` in dilute HCI ?

Options

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