What type of documentation must a property manager keep for financial transactions?

The correct choice focuses on the essential documentation that directly pertains to financial transactions. Property managers are responsible for maintaining accurate records of all financial activities associated with the management of properties. This includes invoices, which detail the services rendered and amounts owed, receipts, which confirm payment made for services or expenses, and bank statements, which reflect all transactions that occur within the property management's bank accounts. Maintaining these documents not only aids in ensuring transparency and accountability in financial dealings but is also crucial for tax preparation and compliance with financial regulations.

In contrast, the other options include documents that, while important for various aspects of property management, do not specifically relate to financial transactions. Contracts and agreements are vital for defining the terms of relationships with tenants and vendors but are not themselves records of financial transactions. Inspection reports and tenant applications serve to document the condition of the property and tenant qualifications respectively, and do not illustrate financial exchanges. Similarly, marketing materials and advertising expenses are related to promoting the property but are not direct documentation of financial transactions.