Answer:
D. Signing up for an online class.
Step-by-step explanation:
Signing up for an online class is an example of investing in yourself. Investing in yourself means taking actions to improve your skills, knowledge, or abilities in order to increase your value or potential for success. By signing up for an online class, a college student is taking the time and effort to learn new material and gain new skills that may benefit their academic or career goals. This type of investment in oneself can lead to long-term personal and professional growth.