Your firm has been engaged to conduct an audit of the financial statements of Sigma Real Estate for the month ending June 30, 20x0. The examination of the monthly rent revenue is an important aspect of the audit engagement. The following rent revenue information was prepared by the controller of Sigma and submitted to you for your information. SIGMA REAL ESTATE STATEMENT OF RENT REVENUE FOR MONTH ENDED JUNE 30, 20x0 Gross Apartment Rents (Schedule A) Less Vacancies (Schedule B) Net Apartment Rentals Less Unpaid Rent For June (Schedule C) Subtotal Add Prepaid Rent Collected (Apt. 205) Total Cash Collected 1,750,000 21,000 1,729,000 10,000 1,719,000 600 1,719,600 Schedules A, B, and C are available to you but are not reproduced here to save space. Assume that someone else has studied and evaluated the system of internal control and has determined that the system can be relied upon to produce reliable accounting information. The company uses a separate bank account to deposit cash received from rental operations