Which Is a Disadvantage to Using Bacteria as a Source

Which is a disadvantage to using bacteria as a source of proteins for purification?

A) Molecular biology techniques can be used to overexpress the protein in these cells
B) Proteins can be extracted from the cells themselves, or from the media in which the cells are grown
C) differences in post-transcriptional modifications may occur
D) They grow more quickly than plant or animal tissue
E) There are fewer ethical issues involved in using bacterial cells for experimentation