The given figure represents the stomach of ruminants with its four chambers labelled as P, Q, R and S. Which chambers allow grazing animals like sheep, cattle etc. to efficiently digest cellulose, a common carbohydrate in plants and how ?
(A) P, Q, S; these chambers secrete cellulase enzyme.
(B) P and Q; these chambers contain billions of bacteria that digest cellulose.
(C) R and S; these chambers contain billions of bacteria that digest cellulose.
(D) P and Q; these chambers secrete cellulase enzyme.