The colour of copper carbonate is:

The correct answer is green,option C i.e CuCO₃ which exists ,on account of atmospheric corrosion, in the form of basic copper carbonate, CuCO₃. Cu(OH)₂ is green in colour. The green colour is mainly attributed to the hydroxide, Cu(OH)₂ layer.

Hence, the correct colour  is given by option B.