Answer:
C. at the intersection of at least two constraints.
Explanation:
Every linear equation has an objective function, further it has the constraints.
In a linear equation when we find the value of constraints where, the value of at least two constraints shall meet, in order to find the solution.
This provides a solution set as when they intersect there are chances of solution, and accordingly even the objective function is easily achieved.
Accordingly the best set which fulfills the objective function where the constraints are also matching the criteria, there lies a solution set.
