In an essay, the main topics are typically previewed in the introduction. The introduction sets the stage for the essay by presenting the main idea or thesis statement, and it outlines what the reader can expect in the body of the essay. The body of the essay contains the details and supporting arguments that elaborate on the main topics introduced. The hook is a part of the introduction designed to grab the reader's attention, while the conclusion summarizes the main points and reinforces the thesis at the end of the essay.
So, to answer your question, the correct responses are:
- Introduction (for previewing main topics)
- Body (for presenting details and supporting arguments)