What Is an Advantage of Using the Lac Regulatory Regions

What is an advantage of using the lac regulatory regions to control the expression of exogenous proteins in bacterial cells?

A) Expression can be controlled by the addition of an inducer to the media.
B) It works in both bacterial and mammalian cells.
C) By using this regulatory region eukaryotic genomic DNA can be used for expression in bacterial cells.
D) Host regulatory mechanisms are not effective when this regulatory regions are cloned into a plasmid.