Task: Question Answering
Input (English): Problem: a retailer marks her goods in such a way that the profit made by selling 50 articles is equal to the selling price of 20 articles . what is the percentage of profit made by the retailer ? 
Options: a ) 66.67 % , b ) 33.33 % , c ) 40 % , d ) 25 % , e ) 20 %
Output (English): a