Al is a medical doctor who conducts his practice as a sole proprietor. During $2022,$ he received cash of $$436,800$ for medical services. Of the amount collected, $$54,000$ was for services provided in $2021.$ At the end of $2022,$ Al had accounts receivable of $$98,200,$ all for services rendered in $2022.$ In addition, at the end of the year, Al received $$18,000$ as an advance payment from a health maintenance organization $($HMO$)$ for services to be rendered in $2023.$

a$.$ Compute Al's gross income for $2022$ using the cash basis of accounting.

b$.$ Compute Al's gross income for $2022$ 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