How is the function of dialysis tubing similar to the small intestine?

I think that both the dialysis tubing and the small intestine are selectively permeable. Which means they allow only some and not all materials to pass through; for example; glucose which is a simple molecular sugar; will pass through, however larger molecules such as starch can not pass through. A dialysis tube is a semipermeable membrane that allows molecules of certain size to get in or out, while keeping molecules above that size in. They are often used to remove impurities from preparations of proteins or other macromolecules and also to normalize pH of a preparation. 

According to edgenuity, the answer is c.