Which of the following pairs is not distinguished by passing `H_(2)S` ?
A. `Hg^(2+),Pb^(2+)`
B. `Cd^(2+),Pb^(2+)`
C. `Sb^(2+),Cd^(2+)`
D. `Zn^(2+),Mn^(2+)`

Which of the following pairs is not distinguished by passing `H_2 S`?
A. Hg,Pb
B. Cd,Pb
C. As,Cd
D. Zn,Mn