Answer:
3. The most important idea.
Explanation:
The central idea of any passage or text is the most important point or topic that the passage or text is talking about. It states the purpose of the whole text or passage.
The central idea is not the same as the main topic. The main topic is the topic that the text but the central idea is the main idea of what the text or passage or paragraph is about.
For instance, in a passage about birds, the main topic is "birds" but the central idea can be about how birds are, or how they help the environment, or how they migrate from one place to another, depending on the passage.
Thus, the correct answer is option 3.
