What is the mechanism of action of the BCA colorimetric assay?

A$.$ The formation of an electrostatic complex between the dye and the arginine residues of a protein

B$.$ The formation of a complex between the dye and $C{u}^{2+}$ which is a product of oxidation generated by the protein

C$.$ The formation of a complex between the dye and $C{u}^{+}$which is a product of reduction generated by the protein.

D$.$ The formation of a redox reaction between the protein and the dye.