According to paragraph 8, which of the following statements is supported by studies of individual meerkats' guarding behavior? A. Solitary meerkats spend more time on foraging than ones belonging to a group, but they also watch for predators some of the time. B. Individual animals in large groups tend to spend more time on guard duty than ones in small groups. C. The time spent watching for predators increases a meerkat's personal safety even when the animal is solitary. D. Sentinels prefer to spend their guarding time as solitary individuals rather than as members of a large group.