The key distinction between Irish labor relations and labor relations in Great Britain is:

A) The lack of emphasis on voluntarism
B) The friendlier relations between management and labor
C) A rising union density rate
D) The inclusion of social partnership between management, labor and the government

The key distinction between Irish labor relations and labor relations in Great Britain is the inclusion of social partnership between management, labor, and the government. In Ireland, there is a strong emphasis on social partnership where government, employers, and unions work together on policy issues that affect the economy and the workforce. This approach is not present in Great Britain, where there is a more adversarial relationship between management and labor. Therefore, option D is the most appropriate answer.