Unlike most excavates, Giardia trophozoites have no oral groove and are unable to form food vacuoles. Thus, we should expect its nutrition (mostly glucose)to come from

A) its mitosomes.
B) endosymbiotic cyanobacteria.
C) the ventral disk by which it adheres to the intestinal lining.
D) osmosis involving aquaporins.
E) plasma membrane proteins that are transporters or pumps.