The student council sent its members on four fields trips during the school year. the number of buses needed to transport the members on each trip is a function of the number of members who went on each trip. the function consists of only the ordered pairs (52, 3), (72,4), (86, 5), and (105, 6) what is the domain for this situation?

a. {52, 105}
b. {3, 4, 5, 6}
c. {52, 72, 86, 105}
d. {3, 4, 5, 6, 52, 72, 86, 105}