下列结构体类型说明和变量定义中正确的是( )。

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;