Outermost electronic configurations of four elements A, B, C, D are given below :

(A) $$3 s^{2}$$

(B) $$3 s^{2} 3 p^{1}$$

(C) $$3 s^{2} 3 p^{3}$$

(D) $$3 s^{2} 3 p^{4}$$

The correct order of first ionization enthalpy for them is :

In neutral or alkaline solution, $$\mathrm{MnO}_{4}^{-}$$ oxidises thiosulphate to :

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

The structure of A in the given reaction is :