Which of the following statements about lac operon in e.coli is true?

• A. Promoter is the binding site for the lac repressor
• B. Operon is only switched on in the absence of lactose in the growth medium
• C. β-galactosidase is only produced in large quantities when the lac repressor is bound to the operator
• D. Lac operon mRNA is a polycistronic mRNA