The price of fuel may increase due to demand and decrease due to overproduction. Marco is studying the change in the price of two types of fuel, A and B, over time. The price f(x), in dollars, of fuel A after x months is represented by the function below:

f(x) = 2.15(0.98)x

Part A: Is the price of fuel A increasing or decreasing and by what percentage per month? Justify your answer.

Part B: The table below shows the price g(m), in dollars, of fuel B after m months:

m (number of months) 1 2 3 4
g(m) (price in dollars) 4.19 3.98 3.78 3.59

Which type of fuel recorded a greater percentage change in price over the previous month? Justify your answer.