26. A research group at NCHU has isolated “Protein S” from the wall of a human stomach. In order to learn how to synthesize stomach tissues in the lab, the researchers determined the sequences of amino acids of Protein S and created a functional mRNA template to translate Protein S in vitro. After several attempts, they were able to translate a correct copy of the polypeptide chain in the lab, however, it took several days for the protein to fold into its native structure. The scientists observed that many copies of Protein S were folded from polypeptide chains every minute in vivo. What is NOT a possible explanation for this difference in folding times?
(A)The temperature in vitro is too low
(B)The in vitro study lacks a functional tRNA molecule
(C)The pH in vitro is too high
(D)There is no key enzyme in the in vitro study