单选题 It is believed by many that all these years the INS ______.

A、 has been serving two contradictory functions.
B、 has been too liberal in granting visas to tourists and immigrants indiscriminately.
C、 has over-emphasized its service functions at the expense of the nation's security.
D、 has ignored the pleas of the two powerful lobbies.

【正确答案】 C

【答案解析】[精解] 本题是一道细节题。参看文章最后一段“One reason for the division， supporters say，is that the INS has in recent years become too focused on serving tourists and immigrants”
A．有两种相互矛盾的功能。
B．不带有任何偏见性地，很开明地把签证发给旅游者和移民。
C．总是过多强调它的服务功能而忽视了国家的安全。与原文的意思一致。
D．已经忽略了两个政党的要求。