单选题 Although Kerry has had no formal education, he is one of the ______ businessmen in the company.
A. alertest B. sternest C. nastiest D. shrewdest

【正确答案】 D
【答案解析】alert保持警觉。stern严厉的，苛刻的。nasty下流的，猥亵的。shrewd精明的。