单选题 One of the recurrent frustrations and tragedies in the history of thought is caused by the uncertainty______to solve a given problem by traditional methods previously applied to problems which seem to be of the same nature.
A. that is possible B. that it is possible
C. whether it is possible D. about what is possible

【正确答案】 C

【答案解析】[解析] 根据题意，uncertainty后面的句子是对它的详细表述，而只有whether能体现不确定性，故正确答案为C。