Which of the following compound does not give test of sulphate ion in aqueous solution?

Which of the following compound is expected to yield a white precipitate with ${\mathrm{AgNO}}_3$ solution :
(a) ${\mathrm{PtCl}}_4·4{\mathrm{NH}}_3$
(b) ${\mathrm{CoCl}}_3·3{\mathrm{NH}}_3$
(c) Impure chloroform
(d) Vinyl chloride
(e)

(f) Carnallite

The effective atomic number of $\mathrm{Cr}$ in $\mathrm{Cr}(\mathrm{CO}{)}_6$ is:

Complex ion square planar geometry: