Scenario 13-12 If Farmer Brown Plants No Seeds on His Farm, He

Scenario 13-12
If Farmer Brown plants no seeds on his farm, he gets no harvest. If he plants 1 bag of seeds, he gets 5 bushels of wheat. If he plants 2 bags, he gets 9 bushels. If he plants 3 bags, he gets 12 bushels. A bag of seeds costs $120, and seeds are his only cost.
-Refer to Scenario 13-12.Farmer Brown's total-cost curve is

A) increasing at an increasing rate.
B) increasing at a decreasing rate.
C) increasing at a constant rate.
D) decreasing.