Al is a medical doctor who conducts his practice as a sole proprietor. During 2020, he received cash of $322,800 for medical services. Of the amount collected, $60,000 was for services provided in 2019. At the end of 2020, Al had accounts receivable of $91,400, all for services rendered in 2020. In addition, at the end of the year, Al received $9,000 as an advance payment from a health maintenance organization (HMO) for services to be rendered in 2021.

a. Compute Al's gross income for 2020 using the cash basis of accounting. $

b. Compute Al's gross income for 2020 using the accrual basis of accounting. $

c. Advise Al on which method of accounting he should use.

Al should use the of accounting so that he will not have to pay income taxes on the .