All along the way, Jefferson chafed at the jump in prices brought about by "harpies who prey upon travelers" returning to Philadelphia. Inns on the route had upped their rates; ferrymen were charging extra to transport people and carriages across rivers. In the end, Jefferson estimated that it cost him nearly eighty dollars just to get to Germantown. What was the cause of the jump in prices?

A. the cost of ferry boat
B. the yellow fever outbreak
C. the number of people traveling
D. the amount of heat, rain, and dust