The constraints of a two-variable linear programming problem are stated here: X 1; Y 1; X + Y 9. Which of the following statements regarding the (X, Y) points is NOT TRUE?

1. The optimal solution might be X=1, Y=8
2. The optimal solution might be X=4, Y=4
3. The optimal solution might be X=1, Y=1
4. The optimal solution might be X=8, Y=1
5. We need to know the objective function to make a better statement.
6. All of the above are TRUE

Please explain why they are correct or wrong.