When Plasmids Are Used to Produce a Desired Protein

When plasmids are used to produce a desired protein,

A) the desired gene is inserted into the plasmid and the plasmid is returned to the bacterium by transformation.
B) the plasmids are inserted into the bacterial chromosome.
C) the bacterial genome and plasmid are inserted into the genome of the cell containing the desired gene (often the cell of a plant or animal) .
D) the plasmids multiply and produce the protein outside of the bacterium.