Test analysis: Because,, so,. If the interval [0, 1] is divided into three segments [0, 1], [0, 1], then at least two values of C 1, C 2, C 3 and C 4 fall in the same cell (pigeon hole principle). So be content. Yes, at least one. So choose C.

Comments: Difficult problem, this problem originated from the examination questions of Anhui Mathematics Competition in 2009, and it is difficult to explore ideas.