阅读下列短文, 从给的四个选项 (A、B、C和D) 中, 选出最佳选项。
Working with a group of baboons (狒狒) in the Namibian desert，Dr.Alecia Carter of the Department of Zoology，Cambridge University set baboons learning tasks involving a novel food and a familiar food，hidden in a box.Some baboons were given the chance to watch another baboon who already knew how to solve the task，while others had to learn for themselves.To work out how brave or anxious the baboons were，Dr.Carter presented them either with a novel food or a threat in the form of a model of a poisonous snake.
She found that personality had a major impact on learning.The braver baboons learnt，but the shy ones did not learn the task although they watched the baboon perform the task of finding the novel food just as long as the brave ones did.In effect，despite being made aware of what to do，they were still too shy to do what the experienced baboon did.
The same held true for anxious baboons compared with calm ones.The anxious individuals learnt the task by observing others while those who were relaxed did not，even though they spent more time watching.
