【单选题】

Ruminants--cattle, bison, sheep, goats, deer, antelopes, and giraffes--have a large four-chambered stomach that enables them to digest fibrous plant matter. When a ruminant first swallows a mouthful of grass or leaves, the food enters the stomach’s first chamber, the rumen, where bacteria start to break down the cellulose-rich matter and form it into small balls of cuD、The ruminant periodically returns the cud to its mouth where it is chewed at length to crush the fibers, making them more accessible to further bacterial action. The ruminant then reswallows the cud, which passes through the other three chambers of the stomach for further digestion.

5. Which sentence below best expresses the essential information in the highlighted sentence in the passage
A．Ruminants eat continuously, spending long periods eating grass and chewing their cud in order to access the nutrients.
B．The bacterial action begins when the ruminant puts the cud in its mouth and starts the long process of chewing.
C．The ruminant’s strong teeth must crush the plant fibers in the cud in order to neutralize the cud’s harmful bacteriA、
D．The cud is sent back to the ruminant’s mouth and chewed extensively so that the fibers can be digested more easily.