一个完整的尺寸包括尺寸界线、、和 三要素

A. struct ss { char flag; float x; } ; ss a,b;
B. struct ss{ char flag;float x;}; struct ss a,b;
C. struct { char flag; float x; }ss; ss a,b;
D. struct { char flag;float x;}ss;struct ss a,b;

A. 4
B. 8
C. 12
D. 13