Answer :
The central idea in the text refers to the idea which is emphasized by the author to be remembered. The central ideas are helpful in stating the main ideas that are the reader has to imply the key idea by making inferences to what the reader knows already. The central idea is not just the topic but it details into a complete sentence.
It can be found at the end of the text, at the beginning of the text or implied through sentences by not stating.
Therefore, Readers must consider the topic and supporting details to determine the central idea in an informational text.