Answer:
b. region of DNA consisting of the promoter, the operator, and coding sequences for structural proteins.
Explanation:
Operon is a segment of DNA that carry groups of genes coding for related proteins. An operon consists of an promoter, operator and coding sequences for structural proteins (regulatory and structural genes).
The promoter is the region in operon where RNA polymerase binds and initiates the process of transcription.
Regulatory DNA sequences are binding sites for regulatory proteins that control the expression of the operon "up" or "down." and structural genes code for proteins needed for cell function such as lactose metabolism.
Regulatory proteins acts as a repressor and when bind to operator, blocks the forward movement of RNA polymerase on the DNA.
Hence, the correct option is b.
