Let x represent the amount of feed type I and y the amount of feed type II to be utilized. Our goal is to minimize the following:
C = 4x + 3y
while adhering to these constraints:

Analyzing the graph of these four constraints yields corner points at (0, 5), (1, 2), and (4, 0).
Testing the objective function at each corner point to find the minimum:
For (0, 5):
C = 4(0) + 3(5) = $15
For (1, 2):
C = 4(1) + 3(2) = 4 + 6 = $10
For (4, 0):
C = 4(4) + 3(0) = $16.
Thus, the combination that results in the lowest cost is one bag of feed type I and two bags of feed type II.