一道填空机经的疑问！！

zjusquanchyUID: 3683452

Peoples’ decisions about childbearing depend on innumerable personal considerations and societal factors, yet even knowing this, demographers are often ______: their projections of birth rates frequently turn out to be embarrassingly at odds with reality.
A. sanguine
B. flummoxed C. inconsistent D. overconfident E. heartened
F. confounded

题目如上，网上的答案给的是BF，我觉得AD更佳合理啊

逆流的鱼ywjUID: 3712130

这个题题干貌似不难懂， 选的应该是innumerable的反面。前面讲innumerable，然后yet转折。冒号表解释，their projections of birth rates frequently turn out to be embarrassingly at odds with reality就是解释这个词的。我也没选对，看来还是单词不过关

逆流的鱼ywjUID: 3712130

sanguine：乐观的，确信的，free from doubt。显然不合理
overconfident在感情上倒是没错，但是不能体现出at odds with reality，并且也不是innumerable的反面