单项选择题

以下程序的输出结果是
char cchar(char ch)
if(ch>=’A’&&ch<=’Z’) ch=ch-’A’+’a’;
return ch;
main ( )
char s [] = "ABC+abc=defDEF" , *p=s;
while (*p)
*p=cchar(*p);
p++;

printf "%$\n", s);

A.abc+ABC=DEFdef
B.abc+abc=defdef
C.abcABCDEFdef
D.abcabcdefdef