A used car salesman purchases a car from its previous owner at a price of $4,500, although the owner was willing to sell it for as little as $4,000. The salesman later sells the car to a new buyer for $6,000, although that buyer was actually willing to pay up to $6,500. What percentage of the value created by the trade is captured by the buyer who purchases the car from the used car salesman?
a) 20%
b) 25%
c) 60%
d) 30%