Task: Question Answering
Input (English): Problem: a company wants to spend equal amounts of money for the purchase of two types of computer printers costing $ 400 and $ 350 per unit , respectively . what is the fewest number of computer printers that the company can purchase ? 
Options: a ) 11 , b ) 13 , c ) 15 , d ) 17 , e ) 19
Output (English): c