Answer:
a.
Step-by-step explanation:
a because a known fact helps support your thesis statement. the rest are negotiable, but mostly not acceptable. b, you need a solid claim, not just one that could be true but you aren't sure. c, you can have a question to solve, but it isn't needed 100% of the time and as you get older, most of the time your instructor won't want a question. and d isn't right either because you summarize your topic in you concluding paragraph, not your statement.