Define optimal solution in a linear programming problem

Hint: The solution which gives the maximum or the minimum objective function value is the Optimal Solution.

An optimal solution to a linear program is the solution which satisfies all constraints with maximum or minimum objective function value
In simpler words,
In a linear programming question we are given an objective function, some constraints and we have to find minimum or maximum values.
So after applying the constraints we get a feasible region which is the set of all solutions which satisfies all the constraints.
Now using the extreme points in the region, the solution which gives the maximum or the minimum objective function value is the Optimal solution.

Note: Every linear program has an extreme point that is an optimal solution but it is not necessary that we are able to find it.