一个IPv6地址为21DA:0000:0000:0000:02AA :000F:FE08:9C5A，如果采用双冒号表示法，那么该IPv6地址可以简写为

A．0x21DA::0x2AA:0xF:0xFE08:0x9C5A

B．21DA::2AA:F:FE08:9C5A

C．0h21DA::0h2AA:0hF:0hFE08:0h9C5A

D．21DA::2AA::F::FE08::9C5A