Researchers have found a human protein (Protein X) that is a useful therapeutic for certain diseases. Protein X doesn't have any significant post-translational modifications and is a relatively small and water-soluble, globular protein. Therefore, Protein X can be expressed in its active form in the bacteria Escherichia coli. Expressing Protein X in and purifying it from E. coli will make it a much more affordable therapeutic. In order to do this, the researchers sequenced the mature mRNA that translates for Protein X in order to get the nucleotide sequence for the mature mRNA that codes for Protein X. They are now going to insert this sequence into a plasmid and transform that plasmid into E. coli , and then express and purify the protein. Which of the following should they also do before they insert the sequence into a plasmid and then into E. coll? Choose one or more: O A. If the mRNA contains a UGA stop codon, then change it to a UAA stop codon. O B. Add a sequence to encode an affinity tag (such as 6 histidine amino acids) at one end of the gene for Protein X. O C. Synthesize the DNA that is complementary to the mature mRNA sequence, and insert that into the plasmid instead of RNA. O D. Change most of the AAA codons that encode for the amino acid lysine to AAG codons.