A basic feasible solution of a linear programming problem is said to be ______ if at least one of the basic variable is zero generate degenerate infeasible unbounded

Given the following statements with respect to linear programming problem: S1: The dual of the dual linear programming problem is again the primal problem S2: If either the primal or the dual problem has an unbounded objective function value, the other problem has no feasible solution S3: If ... the two problems are equal. Which of the following is true? S1 and S2 S1 and S3 S2 and S3 S1, S2 and S3

The following Linear Programming problem has: $\text{Max} \quad Z=x_1+x_2$ Subject to $\quad x_1-x_2 \geq 0$ $\quad \quad \quad 3x_1 - x_2 \leq -3$ $\text{and} \quad x_1 , x_2 \geq 0 $ Feasible solution No feasible solution Unbounded solution Single point as solution