To avoid the precipitate of hydroxide of `Ni^(2+),Co^(2+),Zn^(2+)` and `Mn^(2+)` along with these of `Fe^(3+),Al^(3+)` and `Cr^(3+)` the third group solution should be
A. Heated with a few drop of cone `HNO_(3)`
B. Treated with excess of `NH_(4)CI`
C. Conccotrated
D. None of these