9.Which expression in following statements is not correct?（

9.Which expression in following statements is not correct?（ ）
A．char str[10]; str="string";
B．char str[ ]="string";
C．char *p="string";
D.char *p; p="string";
请说明原因谢谢
12.Which is the output result of the following program code（ ）
char s[ ]="student";
printf(“%s%d”,s+3,sizeof(s));
A．student7 B． dent7 C．dent8 D.student8
这题答案是什么呢