Final answer:
The Accounts Receivable Report provides details on unbilled sales, owed amounts, and payments received. It is the most relevant document for this query about the company's invoicing and payment status over specific periods.
Step-by-step explanation:
The correct answer is A) Accounts Receivable Report. This type of report provides detailed information about outstanding invoices, which includes unbilled sales activity and what customers currently owe. If you want to know how much has been paid into the business in the last 30 days, you would also refer to the accounts receivable report as it records payments received. However, for a comprehensive view of overall cash flow, including details on money received and spent, you would check the Cash Flow Statement. The Financial Overview might provide a summary, and the Sales Summary would show you total sales, but not specifically unbilled sales and payments.