Explanation
Recent third-party IS audit reports would be most helpful in determining the effectiveness of the IT governance framework of the target company. IT governance is a framework that defines the roles, responsibilities, and processes for aligning IT strategy with business strategy. A third-party IS audit is an independent and objective examination of an organization's IT governance framework by an external auditor.
Recent third-party IS audit reports can provide reliable and unbiased evidence of the strengths, weaknesses, and maturity of the IT governance framework of the target company. The other options are not as helpful as recent third-party IS audit reports, as they may not be as comprehensive, accurate, or current as external audits. References: CISA Review Manual, 27th Edition, page 94