Which is not return optimal solution from the following methodsa.Branch and boundb.Dynamic programming     c.Greedy methodd.Backtracking

The method that does not always return the optimal solution among the ones listed is the Greedy method.

Here's why:

a. Branch and Bound: This method is used for solving optimization problems. It does return an optimal solution because it considers all possible solutions.

b. Dynamic Programming: This method breaks down a problem into simpler sub-problems in a recursive manner. It also returns an optimal solution because it considers all possible solutions for the sub-problems.

c. Greedy Method: This method makes the choice that seems to be the best at the moment, meaning it makes a locally optimal choice in the hope that this choice will lead to a globally optimal solution. However, this is not always the case. Therefore, the greedy method does not always return the optimal solution.

d. Backtracking: This is a type of algorithm for finding solutions to some computational problems, notably constraint satisfaction problems. It incrementally builds candidates for the solutions, but abandons a candidate as soon as it determines that the candidate cannot possibly be extended to a valid solution. The classic textbook example of the use of backtracking is the eight