Which complex is formed when an aqueous solution of $NH_3$ is added to a $CuSO_4$ solution,resulting in a deep blue color?

Low oxidation states of metals in their complexes are common when ligands:

Given below are two statements:
Statement $I$ : $N(CH_3)_3$ and $P(CH_3)_3$ can act as ligands to form transition metal complexes.
Statement $II$: As $N$ and $P$ are from same group,the nature of bonding of $N(CH_3)_3$ and $P(CH_3)_3$ is always same with transition metals.
In the light of the above statements,choose the most appropriate answer from the options given below:

Copper sulphate solution reacts with $KCN$ to give

Which one is the most likely structure of $CrCl_3 \cdot 6H_2O$ if $1/3$ of total chlorine of the compound is precipitated by adding $AgNO_3$ to its aqueous solution?

Considering the complexes $(i) K_2PtCl_6$,$(ii) PtCl_4 \cdot 2NH_3$,$(iii) PtCl_4 \cdot 3NH_3$,and $(iv) PtCl_4 \cdot 5NH_3$,the molar conductivities in aqueous solution follow the order (in $\Omega^{-1} \ cm^2 \ mol^{-1}$):