31. Researchers found a large and polar metabolite X is highly enriched in theextracellular matrix and has a low concentration inside cells. New evidence suggeststhat the metabolite X is transported from the cell to the extracellular matrix. Basedon these findings, wbat is the possible transport mechanism?
(A) passive transport
(B) facilitated transport driven by ATP hydrolysis
(C) primary active transport powered by an ion gradient
(D) secondary active transport and the same transporter transports proton into thecell
(E) secondary active transport and the same transporter transports sodium out ofthe cell