Which of the following are true statements about all linear programs? There will always be an objective function in terms of the decision variables, which must be either maximized or minimized. There will always be a single optimal solution, occurring at a corner of the feasible region. There will always be constraints involving the decision variables there will always be decision variables under the control of the managers. The decision variables will always be greater than or equal to 0. There will always be a feasible region.