In a relation, the input is the number of people and the output is the number
of backpacks.
Is this relation a function? Why or why not?
A. No, because you do not know how many people there are.
B. No, because the same number of people might have a different
number of backpacks.
C. Yes, because each person has one backpack.
D. Yes, because a given number of people always has the same
number of backpacks.