The correct answer is A. A topic sentence states the main idea of the essay.
Explanation:
In texts including essays, ideas are usually organized by including an introduction, a set of body paragraphs and finally a conclusion paragraph that together express a global idea or thesis statement in the case of paragraphs. But besides this, each paragraph is composed of a topic sentence that expresses one main idea of the essay, then at least three supporting details that explain the topic sentence and a concluding sentence. This means, a topic sentence is always related to other sentences and details, it is supported by at least three details and also expresses one main idea of the essay. Therefore, the statement that is true is a topic sentence states the main idea of the essay.
