Since Jonas Salk came up with his polio vaccine, infantile paralysis has virtually disappeared from the United States.

A．surfaced with

B．raised the price of

C．discovered

D．elevated

与其他社会规范相比，法律规范的特征有( )。

A．法律是由国家强制力保证实施的行为规范

B．法律是规定权利和义务的行为规范

C．法律是由国家制定或认可的行为规范

D．法律是调整人的行为和社会关系的行为规范