Which of the following has the GREATEST impact on efforts to improve an organization's security...

The supportive tone at the top regarding security is the greatest impact on efforts to improve an organization’s security posture. This means that senior management should demonstrate their commitment and leadership to information security by setting clear goals, allocating adequate resources, communicating effectively, and rewarding good practices. A supportive tone at the top can also influence the culture and behavior of the organization, as well as foster trust and collaboration among stakeholders12. References = CISM Review Manual 15th Edition, page 1261; CISM Item Development Guide, page 82