Caleb teaches economics at Happy State University and is paid $50,000 per year. He also provides economic forecasts for local businesses for which he charges $100 per hour. Which of the following is true? O All of Caleb's income is salary. O Some of Caleb's income is salary, and some is personal interest. O All of Caleb's income is proprietor's income. O Some of Caleb's income is salary, and some is proprietor's income. O All of Caleb's income is personal interest