以下对结构体类型变量的定义中,不正确的是______。①typedef struct aa{Int n;Float m;}AA;AA td1;②#define AA struct aaAA{Int n;Float m;}td1;③struct{Int n;Float m;}aa;Struct aa td1;④struct{Int n;Float m;}td1;
A.①
B.②
C.③
D.④
正确答案是C