Answer:
The correct answer is letter "C": when the marginal magnitude is below the average magnitude, the average magnitude falls.
Step-by-step explanation:
The average-marginal value is an Arithmetic rule implemented in Economics that states that when the marginal value is above the average value, the average value tends to rise, In case the marginal value is below the average value, the average value tends to fall. The average value remains the same when it is equal to the marginal value.