Read the case study below and choose the best possible answer to the following question.

For the past week, Christopher has been studying for his first American History exam. Christopher plans to transfer and eventually become a pre$-$law major, so his success in this course is very important to him. He has taken a number of steps to make sure he is prepared$-$for example, he met up with friends from class to review their notes as a group, he added in extra study time instead of attending his usual workouts at the gym, and he made sure to eat healthy meals and avoid drinking too much coffee. When he woke up after a full night's sleep the morning of the test, he reassured himself that he had put in a lot of effort and he would do well.

On the day of the test, Christopher attempted to calm his nerves, looked over the entire exam, and made a plan to answer the easiest multiple$-$choice questions first. When it came time to yrite the essay portion of the exam, he created a short outline of what he wanted to say, though he acknowledges that he didn't always stick to his main points. He ended up writing more than he anticipated $($almost two full pages$)$ because he wanted to share everything he knew about the topic.

Christopher admits that he guessed at some of the items on the multiple$-$choice part of the exam. He felt sure he had done well on the essay, but he scored only $30$ out of the $50$ possible points. Overall, Christopher received a grade of $63$ out of $100$ points on the exam.

Question.

Which of the following might have negatively impacted Christopher's test preparation?