根据《素问·脉要精微论》所述，“五脏失强”的病候有（）

A.仓廪不藏

B.头倾视深

C.背曲肩随

D.水泉不止

E.行则偻附

If no other unbiased estimator of the same parameter has a sampling distribution with smaller variance, the estimator can be best described as:（）

A. efficiency.

B. unbiasedness.

C. consistency.