The complex cation which has two isomers is :

The structures of major products A, B and C in the following reaction are sequence.

The graph which represents the following reaction is :

Among following compounds, the number of those present in copper matte is ___________.

A. $$\mathrm{CuCO_{3}}$$

B. $$\mathrm{Cu_{2}S}$$

C. $$\mathrm{Cu_{2}O}$$

D. $$\mathrm{FeO}$$