单项选择题

A.8%枸橼酸钠生理盐水50ml
B.每50ml血中加2%枸橼酸钠生理盐水5ml
C.每50ml血中加3.8%枸橼酸钠生理盐水10ml
D.每50ml血中加3.8%枸橼酸钠生理盐水15ml
E.每50ml血中加3.8%枸橼酸钠溶液5ml