detailed solution

Correct option is D

(a) I group basic radicals precipitate as chlorides because $\left({\mathrm{Ag}}_{+},\mathrm{Pb}2+\text{ and }\mathrm{Hg}2+\right)$

from the first set of basic radicals are precipitated as their chlorides because the solubility product of their chlorides, AgCl, PbCl₂, and Hg₂Cl₂, is lower than that of all other chlorides, which are present in solution in hot water.

(b) IV group basic radicals precipitates as sulphides because sulphide ion concentration increases. Since there are more ionic products than solubility products due to the higher sulphur ion concentration, Group IV radicals precipitate as sulphides.

(c) V group basic radicals precipitate as carbonates due tothe presence of $\left({\mathrm{NH}}_4\mathrm{OH}\right)$.The carbonates of V group basic radicals precipitate, keeping the pH of the solution basic. In the presence of $\left({\mathrm{NH}}_4\mathrm{OH}\right)$ the basic radicals of the V group precipitate as their carbonates.

Hence the correct option is D.