Answer:
D It shares the main idea of an essay and introduces reasons to support the topic.
Step-by-step explanation:
The controlling idea in an informative essay is the opinion of an author about the given topic. It also talks about how the story will be developed and explain the reason for writing the sentence or article.
Therefore, the purpose of a controlling idea in an informative essay is to share the main idea of an essay and introduces reasons to support the topic.