4. (6 pts) Consider the maximum flow in a given network between two designated nodes s and t. For each of the following statements, either explain why it is true or provide a counterexample. Hint: you can use max flow-min cut theorem a) (3 pts) If the capacity of every arc is even, then the value of the maximum flow must be even. b) (3 pts) If the capacity of every arc is odd, then the value of the maximum flow must be odd