Task: Question Answering
Input (English): Problem: a farmer has enough food to feed her 1000 cows for 50 days . after 10 days some of the cows run away and the food was now enough for the same period of 50 days as before . how many cows ran away ? 
Options: a ) 300 , b ) 200 , c ) 500 , d ) 400 , e ) 250
Output (English): b