Whenever marginal cost is greater than average total cost, A. average total cost is rising. B. marginal cost is falling. C. average total cost is falling. D. Both b and c are correct.

A. average total cost is rising.

Explanation:

Whenever marginal cost is more than average cost it means it costs more to produce a unit now compared to the average cost of the previous units. Lets assume that a company produces 3 units of a good.

The first unit costs $1

The second unit costs $2

The third unit costs $3.

The average cost is (1+2+3) / 3=2

Now if the marginal cost for producing a unit is more than the average cost for example if the marginal cost is 4, then this will mean that average total cost is rising. we can mathematically check this.

The first unit costs $1

The second unit costs $2

The third unit costs $3.

The fourth unit costs $4

Average cost = (1+2+3+4) / 4=10/4=2.5

Here we see that the average cost increased from 2 to 2.5 because marginal cost was greater than average cost.