50. According to this passage, which of the following statements is true?
(A) Animals in zoos are often bored and, as a result, some become aggressive.
(B) Many of the living exhibits in zoos are designed for profit, not for other noble goals.
(C) In discussion about conservation, the voice of the local communities is not listened to.
(D) Zoos began as amusements and finally tapped into a wealthy societal appetite for entertainment.