TOEFL Reading: ETS-TOEFL阅读机经 - FTDJWD03ZCD61P2KL$

According to paragraph 1, which of the following is true about the ceremonial centers established by the Olmecs A. The centers served as the burial places of ancient Olmec rulers. B. The inhabitants of each center had little or no contact with those in other centers. C. The centers featured major works of art and architecture that were made to last. D. The first and most important centers were built in the highlands.