Listen to the below dialogue carefully and then choose the best answer for the question. You will hear once only.

A.山梨酸
B．聚山梨酯
C．羟苯酯类
D．苯扎溴铵

A.分子态苯甲酸抑菌作用强
B．相同浓度的苯甲酸与苯甲酸钠盐抑菌能力相同
C．苯甲酸与苯甲酸钠盐在pH为6时抑菌活性最强
D．苯甲酸抑制酵母菌的能力较尼泊金类强