Rabbits Produce Two Types of Droppings: Fecal Pellets, Which Are

Rabbits produce two types of droppings: fecal pellets, which are waste products of digestion, and cecotropes, which they re-ingest. Ruminants do not re-ingest any feces. What is the difference between the two that requires re-ingestion by rabbits, not cows?

A) Ruminants use microorganisms to digest cellulose and release cellular contents into the stomach to be digested; rabbits secrete cellulose-digesting enzymes into their hindgut so products of digestion can be absorbed.
B) Rabbits use microorganisms in their hindgut to digest cellulose; ruminants secrete cellulose-digesting enzymes into their stomachs.
C) Rabbits are hindgut fermenters, therefore nutrients would be lost if the products of fermentation in the cecum were not eaten; ruminants are foregut fermenters, and the products of digestion are absorbed in the small intestine.
D) Rabbits, which are hindgut fermenters, consume a carnivorous diet, and ruminants, which are foregut fermenters, have a cellulose-based diet, and their respective digestive systems are adaptations to these two dietary specializations.