What row are you ________?

1. A.
   at
2. B.
   on
3. C.
   in
4. D.
   to

-What row are you in? 

-We are in ________ .

[　　]

-What row are you in? 

-We are in ________ .

[　　]

—__________are you in?　　　

—I'm in Class Four.

[　　]

A. What number　　    　B. What grade

C. What class　　　　 　D. What row