You Have Driven 850 Miles on a Vacation and Then

You have driven 850 miles on a vacation and then you notice that you are only 50 miles from an attraction you hadn't known about, but would really like to see. In computing the opportunity cost of visiting this attraction you had not planned to visit, you should include

A) both the cost of driving the first 850 miles and the next 50 miles.
B) the cost of driving the first 850 miles, but not the cost of driving the next 50 miles.
C) the cost of driving the next 50 miles, but not the cost of driving the first 850 miles.
D) neither the cost of driving the first 850 miles nor the cost of driving the next 50 miles.