Final answer:
The assertion that is not a financial one made by management is the 'Effectiveness of internal control'; other options like valuation, completeness, and existence are financial assertions.
Step-by-step explanation:
The option that is not a financial assertion made by management is 'B. Effectiveness of internal control'. Financial assertions are claims made by a company's management regarding the condition of its financial statements; they relate to transactions and account balances. These assertions typically include valuation, which deals with whether assets, liabilities, equity, revenue, and expenses have been included in the financial statements at appropriate amounts; completeness, which assures that all transactions and accounts that should be presented in the financial statements are so included; and existence, which concerns whether assets or liabilities of the company exist at a given date.
While the effectiveness of internal control is critical to the reliability of financial statements, it is not itself a financial assertion. Instead, it is a part of the broader internal controls that management implements to ensure the accuracy and completeness of the financial reporting process.