单项选择题
A.900pg/mlB.450pg/mlC.300pg/mlD.1800pg/ml
A.300pg/mlB.450pg/mlC.900pg/mlD.1800pg/ml
A.利钠肽B.B型利钠肽C.N端-B型利钠肽D.N端-B型钠尿肽原