Task: Question Answering
Input (English): Problem: marginal cost is the cost of increasing the quantity produced ( or purchased ) by one unit . if the fixed cost for n products is $ 12000 and the marginal cost is $ 200 , and the total cost is $ 16000 , what is the value of n ? 
Options: a ) 20 , b ) 50 , c ) 60 , d ) 80 , e ) 100
Output (English): a