Which of the following is NOT a means of clearing a Certifying Officer's pecuniary liability?

The correct answer is that showing that the investigation failed to prove negligence is not a means of clearing a Certifying Officer's pecuniary liability.

To understand this, it's important to recognize what pecuniary liability entails. A Certifying Officer is responsible for ensuring that funds are disbursed correctly, and any failure in this responsibility that leads to a financial loss may result in a liability. In cases where mistakes or failures occur, the burden of proof often lies with the officer to demonstrate that they acted appropriately.

Showing proof of due diligence, for instance, involves demonstrating that the Officer took the necessary steps to prevent any errors, which can mitigate liability. Submitting a timely claim for reimbursement is a standard process to reclaim any incurred expenses or losses resulting from their duties. Providing receipts for expenses also serves to document and justify the financial aspects of their actions.

However, merely stating that an investigation failed to prove negligence does not actively demonstrate the necessary actions taken by the Officer or their compliance with accountability standards. It does not demonstrate their diligence or control over the situation at hand, which are critical in mitigating or clearing liability. Therefore, this option stands out as not contributing to the clearing of a Certifying Officer's pecuniary liability.