Read the excerpt from "Chart Your Own Course.” I remember as a freshman I mistakenly rolled into a class that was meant for juniors and seniors. And there were times when I felt like I could barely keep my head above water. But through it all, I kept that college diploma as my North Star. And four years later, I reached that goal, and then I went on to build a life I never could have imagined for myself. How does Obama’s determined tone affect her credibility in this excerpt? Stating the length of time it took to earn her diploma strengthens her credibility. Convincing audience members to set their own North Star goal weakens her credibility. Mentioning what it felt like to struggle strengthens her credibility. Using figurative language instead of literal language weakens her credibility.