Final answer:
The price of product A is increasing by 25% per year.
Step-by-step explanation:
The price function for product A is given by f(x) = 72 * (1.25)x. To determine whether the price is increasing or decreasing, we need to analyze the exponent, which represents the number of years.
Since the base of the exponent, 1.25, is greater than 1, the function is exponential growth. This means that as the number of years increases, the price of product A will also increase.
Now, let's calculate the percentage increase per year. The rate of growth is given by (1.25 - 1) * 100%, which simplifies to 25%. Therefore, the price of product A is increasing by 25% per year. So, the answer is A) Increasing by 25%.