【名词&注释】
四物汤、主动脉瓣狭窄(aortic stenosis)、胆碱酯酶(cholinesterase)、《临证指南医案》(medical records as a guide to clinical ...)、甲状腺功能亢进症(hyperthyroidism)、有机磷杀虫药中毒(organophosphorus insecticides poisoning)、内膜异位症(endometrium ectopia)
[单选题]诊断有机磷杀虫药中毒(organophosphorus insecticides poisoning)时,全血胆碱酯酶活性应是( )
A. <100%
B. ≤90%
C. ≤80%
D. ≤75%
E. ≤70%