What is the composition of Bordeaux mixture?

Answer: Option C

The composition of Bordeaux mixture is 5lb Copper sulphate + 5lb lime + 50 gallon water.
Bordeaux mixture is a mixture of copper (II) sulphate (CuSO₄) and quicklime (CaO) used as a fungicide. It was invented in the Bordeaux region of France in the late 19^th century, hence named after that.
Bordeaux mixture achieves its effect using the copper ions (Cu²⁺) of the mixture. These ions affect enzymes in the fungal spores in such a way as to prevent germination.
It is sprayed on plants as a preventive treatment; its mode of action is ineffective after a fungus has become established.