Answer:
C. The value of the comic book decreased by an average of $0.04 each month between m = 36 and m = 60.
Step-by-step explanation:
The average rate of change for the function f(x) from
and
is

It is a measure of how much the function changed per unit, on average, over that interval.
Actually, this is the slope of the line passing through two points on the graph of the function.
If the average rate of change of the function f(x) between m = 36 and m = 60 is -0,04, it means that the value of the comic book decreased (because of negative number -0.04) by an average of $0.04 each month (a unit in this case is a month) between m = 36 and m = 60.