Concept:Problem-solving method involves understanding the problem, forming hypotheses, and working backwards to find the solution.Explanation:The person gives half the fruits plus one at each gate. At the end only one fruit remains. To find the starting number, we must work backwards from the last gate. This reverse process is a key step in problem-solving. First, read and understand the relation between gates and fruits given. Then form possible approaches and select the best one. The problem requires going from the end to the beginning, not simply forward. This matches the problem-solving method, where students interpret the situation, decide a strategy, and solve step by step.Answer:D. Problem-solving