Al is a medical doctor who conducts his practice as a sole proprietor. during 2019, he received cash of $334,200 for medical services. of the amount collected, $33,600 was for services provided in 2018. at the end of 2019, al had accounts receivable of $91,400, all for services rendered in 2019. in addition, at the end of the year, al received $11,000 as an advance payment from a health maintenance organization (hmo) for services to be rendered in 2020. compute ai's gross income for 2019 using the cash basis of accounting.