Applying behavioral change management is the greatest challenge to implementing IT governance, as it involves changing the culture, mindset, and behavior of the people who are affected by or involved in IT governance. IT governance is not just a technical or procedural issue, but also a human and organizational one. Therefore, it requires effective communication, education, motivation, and leadership to ensure that the stakeholders understand, accept, and support the IT governance objectives, principles, and practices. The other options are not as challenging, as they can be addressed by following established methods, frameworks, and standards for IT governance. References: : CGEIT Review Manual (Digital Version), Chapter 1: Governance of Enterprise IT, Section 1.2: IT Governance Frameworks and Standards, Subsection 1.2.1: IT Governance Frameworks and Standards Overview, Page 17 : CGEIT Review Manual (Digital Version), Chapter 1: Governance of Enterprise IT, Section 1.4: Implementing and Maintaining an IT Governance Framework, Subsection 1.4.2: Implementing an IT Governance Framework, Page 29 : CGEIT Preparation Tips and the Timelessness of Good Governance1