The vertices of a feasible region are (0, 0), (0, 2), (5, 2), and (4, 0). For which objective function is the maximum cost C fond at the vertex (4, 0)?

1. C = -2x + 3y
2. C = 5x + 3y
3. C = 2x + 7y
4. C = 4x - 3y