Task: Question Answering
Input (English): Problem: company c sells a line of 20 products with an average retail price of $ 1200 . if none of these products sells for less than $ 400 , and exactly 10 of the products sell for less than $ 1000 , what is the greatest possible selling price of the most expensive product ? 
Options: a ) 12000 , b ) 11000 , c ) 10000 , d ) 13000 , e ) 15000
Output (English): b