以下关于枚举类型的使用，正确的是_____ A: enum{mon, tue, sat, thu, fri, wed, sun} day_1; B: enum BOOL{NO, YES};BOOL judge = NO;BOOL decision = 1; C: 有如下定义：enum MONTH{JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC}mon;mon=MAY;语句 printf("%s\n", mon); 将输出“MAY” D: enum WEEKDYA{Sun=7, Mon=1, Tue, Wed, Thu, Fri, Sat }day;Tue=3;day=Tue;