The corner points of the feasible region determined by the system of linear inequalities are (0, 0), (4, 0), (2, 4) and (0, 5). If the maximum value of z = ax + by, where a, b > 0 occurs at both (2, 4) and (4, 0), then:
- a = 2b
- 2a = b
- a = b
- 3a = b




Based on the above information, answer the following questions.