9823 + x = 13200, then x is ?  Pick one.
A) 3327	B) 3237	C) 3337	D) 3377	E) None of these
Answer   x = 13200 - 9823= 
<gadget id="calculator">13200 - 9823</gadget>
<output>3_377</output>
3377   Option: 3377
<result>D</result>
9823 + x = 13200, then x is ?