Answer:
"Even though my family doesn’t have a lot of money, I knew I could get a scholarship if I improved my grades."
Step-by-step explanation:
Although there are several sentences in this passage that could be considered optimistic, this is the one that best conveys an optimistic tone. In this sentence, the speaker tells us that his family does not have a lot of money. Most people would see this negatively, and as an obstacle for achieving their dreams. However, the speaker sees this in an optimistic way, and he is sure that he can get a scholarship if he improves his grades.