I think the answer is C, because if they are speaking clearly then people can fully understand what they are saying.
Answer:
C. It reveals that chimpanzees need some prompting to act selflessly.
Explanation:
The above statement helps in proving the understanding which was gotten about the chimpanzees. Though the chimpanzees renders selfless services most of the time, it could not be possible if there was never an external factor which will push them to act such. <em>For example, when in danger and crying, this would trigger the chimpanzee to assist towards helping the person.</em>
Second paragraph, and all except the first sentence. Hope i could help! :) <span />
Hope the attached articles help
