Correct option is A
Utilizing a tree chart to illustrate the hierarchy of historical events, such as wars, revolutions, or social movements, within a specific era is an effective teaching strategy. Tree charts are particularly suited for visualizing complex information in a structured manner, making them ideal for outlining the chronological order and interrelations among significant historical events. This method helps students understand the causal relationships between different events, the progression of historical phenomena, and the impact of these events over time. By organizing events in a hierarchical structure, students can better grasp the flow of history, identify key moments and turning points, and appreciate the multifaceted nature of historical developments. This visual approach not only enhances comprehension but also aids in retaining information by providing a clear, organized framework for understanding historical narratives.