Using the techniques of genetic engineering,you design a protein you want to accumulate within the ER of yeast cells.To accomplish this goal,you need to

A)do nothing; all proteins go through the ER.
B)incorporate appropriate mannose-6-phosphate groups.
C)incorporate the appropriate DNA sequence(s)to create signal sequences in the mature peptide.
D)incorporate radioactive amino acids into the protein.
E)remove the N-formyl group located at the N-terminus of the polypeptide.