What records must a company keep according to the provided text?

A company is required to maintain annual financial reports as part of its legal obligations and accountability to stakeholders. These reports provide a comprehensive overview of the company's financial performance and position over the financial year, ensuring transparency and compliance with regulatory requirements. Annual financial reports make it possible for shareholders, investors, and other stakeholders to make informed decisions regarding their involvement with the company, as they contain crucial information such as income statements, balance sheets, and cash flow statements.

In contrast, while the other options may be important for specific business operations or internal management, they do not represent universal requirements mandated for all companies. Salaries of all employees might pertain more to human resources management rather than a legal obligation to maintain detailed public financial records. Real estate assessments are typically more relevant to specific industries or when a company holds property as part of its assets, and written communications, while useful for record-keeping, do not have the same regulatory significance as comprehensive annual financial reports. Thus, the focus on annual financial reports reflects the essential legal requirement for companies to provide accurate and transparent financial information.