If you're asking for main idea, the main idea or thesis statement sentence is sentence 1, where they explain what the passage is about.
Here is a screenshot of a graphic of the U.S Government Branches made by me. It is completed and designed following the instructions given. The <u>underlined </u>ideas are the ones that were completed.
The letter following the quotation needs to be capital. This is because what the person said is also a sentence.
Example: As Mark was walking he said, "This is a beautiful day!"
Happy to help!