Explanation:

- Understanding Internal and Independent Auditors:

- Internal auditors are primarily focused on evaluating and improving the effectiveness of internal controls, risk management, and governance processes within the organization.

- Independent auditors focus on providing an external opinion on the financial statements' fairness and legal compliance.

- Option Analysis:

- Option 1 - Cost accounting system: While relevant, internal auditors are more broadly focused on controls.

- Option 2 - Internal control system: Correct, as internal auditors deal extensively with assessing and improving internal controls.

- Option 3 - Legal compliance: More typically assessed by independent or compliance auditors.

- Option 4 - Accounting system: Internal auditors review this but primarily to assess effective control processes, not as a primary focus.

- The correct answer is Internal control system from Option 2.