单项选择题

A.5,7,4′-三羟基黄酮
B.5,7,3,4′-四羟基黄酮
C.3,5,7,4′-四羟基黄酮
D.3,5,7,3′,4′-五羟基黄酮
E.3,5,7,3′,4′,5′-六羟基黄酮