Multiple choice:After the following program runs, input a capital letter Q from the keyboard, and the output result is

After the following program runs, input a capital letter Q from the keyboard, and the output result is @ [b] (2)
```
char ch;
ch=getchar( );
ch=ch-'A'+'a';
putchar(ch);
```
A. Q
B. q
C. A
D. a




A.Q
B.q
C.A
D.a


answer：B