1.【完成句子】Sagan was noted for the vigour of his logic style, especially when criticizing some piece of pseudoscience(伪科学). I remembered a 1973 AAAS meeting at which he destroyed the theories of Immanuel Velikovsky, who was maintaining that only a few thousands of years ago, Venus had repeatedly collided with Earth and Mars; events well noted. Velikovsky said, in the bible.
In Sagan's opinion, Velikovsky might be__________.
A.a member of the National Academy of Science
C.a science populariser