Task: Question Answering
Input (English): Problem: a company plans to gradually replace its fleet of 20 cars with newer models . at the end of every year starting with 2000 it retires 5 of its old cars and buys 6 new models . how many years did it take before the number of older cars left in the company ' s fleet was less than 50 percent of the fleet ? 
Options: a ) 6 , b ) 3 , c ) 2 , d ) 4 , e ) 5
Output (English): c