Final answer:
The underlined sentence 'Review Failure a Stepping Stone to Success' serves as the thesis statement that presents the main idea of the text and the author likely includes it to inform the reader of the essay's perspective.
Step-by-step explanation:
The underlined sentence 'Review Failure a Stepping Stone to Success' in the text seems to align most closely with a thesis statement that not only signals the primary focus of the text but also sets the stage for the author's development of their argument or main idea. Given the placement and function typically associated with a thesis statement, it is reasonable to interpret the author's purpose for including it as option c) Thesis statement; to state the main idea. This foundational element presents the author's central claim or perspective, around which the subsequent details of the essay revolve, informing the reader of the essay's standpoint and what to expect in the discussion that follows.