Ò»¡¢Ñ¡ÔñÌâ

1£®ÒÑ֪ȫ¼¯U£½{1,2,3,4,5}£¬¼¯ºÏA£½{x∈Z|1<x<5}£¬Ôò¼¯ºÏ?_UA£½(¡¡¡¡)

A£®∅                                                      B£®{1,2,5}

C£®{1,5}                                                D£®{1,4,5}