4. which one of the following statements about a topic sentence and a main idea is accurate? a. a topic sentence and a main idea are always the same thing. b. a topic sentence is the central idea of a paragraph, while a main idea is the central idea of an entire text. c. a topic sentence is found in the introduction, while a main idea is found in the conclusion. d. a topic sentence does not change position, but the main idea can be found in multiple places.