Plz answer this and dont get wrong

According to eric shlosser’s introduction to fast food nation what is his book primarily about?

Which of the following is a complex sentence? a. after henry submitted his essay, he realized that he hadn't proofread the last page. b. identity theft is a growing problem, especially among seniors. c. we didn't have enough potatoes for dinner, so we served rice instead. d. jim tried to watch a video on a device connected to a crowded wireless network; as a result, the video stuttered and froze.

Choose the option that includes the main claim in “the american promise”