Which of the following features are associated with posting keys in financial transactions?

The feature associated with posting keys in financial transactions is that they determine the type of posting, specifically whether it is a debit or a credit. Posting keys are essential components in the SAP system as they specify the nature of the transaction being recorded. Each posting key is linked to a specific type of account and indicates how the amounts should be treated in the accounting entries.

By defining whether an entry is a debit or credit, posting keys help to maintain the accuracy of financial statements and ensure that the accounting equation (Assets = Liabilities + Equity) remains balanced. They play a critical role in facilitating proper accounting practices and ensuring that the financial data is correctly recorded in the system.

The other features listed might not accurately represent the specific characteristics of posting keys. For example, while it is true that posting keys must be included for each line item in a financial document, this characteristic is more about procedural requirements rather than a defining feature. Similarly, the validity for the entire accounting document and defining the reporting category could relate to other elements in the financial posting processes, but they do not directly describe the primary function of posting keys.