Task: Question Answering
Input (English): Problem: a certain article of clothing was discounted during a special sale to 4 / 5 of its original retail price . when the clothing did n ' t sell , it was discounted even further to 1 / 2 of its original retail price during a second sale . by what percent did the price of this article of clothing decrease from the first sale to the second sale ? 
Options: a ) 50 % , b ) 33.33 % , c ) 40 % , d ) 16.66 % , e ) 12.5 %
Output (English): c