GRE Text Completion: Manhatton-GRE填空Manhatton - 1H91E5WK17CMZ98C=

Even those accustomed to the austere beauty of mathematics may be daunted by the ____________ with which Bourbaki conducts his proofs. A. celerity B. diligence C. alacrity D. asperity E. inscrutability F. rigor