补体C3的功能是

A．C3转化酶的基质

B．过敏毒素作用

C．趋化作用

D．促进血液凝固

E．起佐剂作用

Obviously, the word "arrangement" underlined in the third paragraph refers to the fact that ______.

A．he was arranged to speak about his involvement

B．a campaign was under way to promote the administration

C．he was paid for speaking on NCLB developments

D．some critics made an arrangement to criticize him