Joe cycles from his house to school at a constant rate of 25 feet per second. The distance from his house to school is 2500 feet.
Which of the following is the most appropriate variable definition in this situation?
a) Let a represent the number of feet Joe has cycled since he left his house.
b) Let d represent distance.
c) Let d represent the number of feet Joe has cycled.
d) Let d represent the number of feet.
e) None of the above.