有以下说明和定义语句： 　　struct student 　　{ int age; char num[8];}; 　　struct student stu[3]={{20,"200401"},{21,"200402"},{10\9,"200403"}}; 　　struct student *p=stu; 　　以下选项中引用结构体变量成员的表达式错误的是（ ）。　

A．typedef struct{int n; char c;}REC;REC t1,t2;
B．struct REC;{int n; char c;};REC t1,t2;
C．typedef struct REC;{ int n=0; char c='A';} t1,t2;
D．stmct{ int n; char c;} REC;REC t1,t2;

A．7
B．3
C．2
D．0