Ruminants Have a Multi-Compartmented Stomach

Ruminants have a multi-compartmented stomach.They have a symbiotic relationship with bacterial organisms resident in the first of four compartments (the rumen) .How do the bacteria help ruminant digestion?

A) They break down cellulose,a complex polysaccharide that would be indigestible without the assistance of bacterial organisms.
B) They increase the rate of movement of contents through the alimentary canal.
C) They maintain a basic pH in the rumen.
D) They do not help with digestion,but benefit from foods eaten by the ruminant.