Concept:Problem-solving requires flexible thinking and trying different approaches. Getting fixed on only one way blocks progress.Explanation:Options A, B, and D all help problem-solving. Thinking aloud clarifies steps, worked examples provide guidance, and brainstorming generates new ideas.However, option C means a person cannot shift perspective. This rigid thinking prevents finding alternative solutions. Hence, it is a major obstacle to solving the problem.Answer:C. Getting stuck at one way of representing the problems