$$M^{2+} + H_2S \to A \text{ (Black precipitate)} + \text{by product}$$
$$A + \text{aqua regia} \to B + NOCl + S + H_2O$$
$$B + KNO_2 + CH_3COOH \to C + \text{by product}$$
Consider the following test for a group-IV cation. The spin-only magnetic moment value of the metal complex C is ______ BM (Nearest integer)