Answer:
B. Microorganisms in their digestive tracts hydrolyze the cellulose to individual glucose units.
Explanation:
Cows are ruminants. They lack the cellulose digesting enzymes. However, they have a stomach with four chambers. The first two chambers of their stomach house symbiotic bacteria and protists. These microbes have the ability to digest cellulose into simple sugars. These simple sugars are then used by the host and the bacteria themselves. The microbes digesting the cellulose produce the enzyme cellulase and breakdown cellulose anaerobically.