Answer :
Answer:
b. Each decision variable must be non-negative in the optimal solution.
Explanation:
This constraint or restriction states that x11, x12, x21, and x22 all must be at least 0 or greater. in other words, they cannot be negative numbers. If the restriction had been > (greater than), then it would mean that all the variables must be positive numbers. But since it is ≥ (greater than or equal to), 0 is a valid option.