A person starts writing all 4 digit numbers .How many times had he written the digit 3? Choose the correct choice from the following options
A) 3700 B) 3800 C) 3900 D) 4000 E) 4100
_ _ _ 3 = 9*10*10   _ _ 3 _ = 9*10*10   _ 3 _ _ = 9*10*10   3 _ _ _ = 10*10*10   900+900+900+1000= 
<gadget id="calculator">900+900+900+1000</gadget>
<output>3_700</output>
3700   3700NSWER:3700
<result>A</result>
A person starts writing all 4 digit numbers .How many times had he written the digit 3?