十一届全国人大常委会第二十一次会议通过了关于修改个人所得税法的决定，个人所得税起征点自2011年9月1日起由2000元提高到3500元。个人所得税起征点提高表明（）

①能更好调节收入差距，实现社会公平

②国家的财政收入将增加

③税收是可以随时变化的

④能提高居民收入水平，促进居民消费

A.①②

B.②③

C.①④

D.②④

Most IP layer-based proxy mechanisms, such as network address translation (NAT), only support uni-directional proxy, from the internal network to external network (the Internet). The proxy establishes the communication channel by (86) IP addresses. The IP addresses must be (87) . These proxy mechanisms prevent applications that must establish return data channels from establishing their data channels, such as, multimedia applications. IP layer-based proxy mechanisms need additional software (88) for each application that uses (89) channels. SOCKS identifies communication targets through domain names, overcoming the restriction of using private IP addresses. SOCKS can use domain names to establish communication between separate LANs, with (90) IP addresses.

（87）是（）

A.routable

B.locatable

C.path-selected

D.road-defined