What Is an Advantage of Using the Lac Regulatory Region

What is an advantage of using the lac regulatory region 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) This regulatory region functions in both bacterial and mammalian cells.
C) By using this regulatory region, eukaryotic genomic DNA can be expressed in bacterial cells.
D) Host regulatory mechanisms are not effective when this regulatory region is cloned into a plasmid.