The proper paragraph structure is A: topic sentence, concrete detail, commentary, concluding sentence.
In this structure:
- The topic sentence introduces the main idea of the paragraph.
- Concrete detail provides specific evidence or examples that support the topic sentence.
- Commentary offers analysis or insights about the concrete details, explaining their significance or how they relate to the main idea.
- The concluding sentence wraps up the paragraph by summarizing the point made or linking it to the next idea.