Select the statements that are true. a. The optimal objective value of a maximization integer-linear program is always greater or equal than that of its LP-relaxation. b. Rounding the optimal solution of the LP-relaxation of an integer-linear program always produce an infeasible solution. c. If the optimal solution of the LP-relaxation of an integer-linear program is integral, then this solution is also the optimal solution of the integer-linear program. Select the statements that are true. a. For any integer-linear program with n binary variables, the maximum number of nodes explored in the enumeration tree of the Branch-and-Bound algorithm is 2 n. b. For any integer-linear program with n binary variables, the maximum number of feasible solutions is 2n. C. For any integer-linear program with n binary variables, at any node in the enumeration tree of the Branch-and-Bound algorithm each of its children nodes has one extra constraint in its formulation