Answer is b,a,d,c,e
Explanation
The Lac Operon is called lactose operon is a cluster of genes with a promoter. The bacteria uses lactose as the source of energy by the proteins coded by genes. This is present in Prokaryotes.
The regulatory gene codes for repressor protein. The repressor binds to lactose and prevent its binding to operator. Thus,RNA polymerase is prevented from binding the promotor. The transcription of genes inhibited . That means correct order is b a d c e