b. An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter
Explanation:
An operon is usually found in prokaryotic organisms. It refers to the functional structure within prokaryotic genome in which multiple different genes are under the control of one promotor. All of the genes are transcribed together which leads to the formation of polycistronic mRNA. Polycistronic mRNA migh undergo splicing to create monocistronic mRNAs which will be translated separately into few products (proteins).
