Which of the following ensure that it was western europe that rose to become the dominant force in global politics
a. the collapse of the ming dynasty
b. the chinese policy of isolation
c. the expansion of feudalism
d. the failure of the crusades

In my opinion the most likely reason why the dominant force in global politics are the nations of Western Europe is because of China's decision to lead a policy of isolation - B. 

China has been a powerful and important nation throughout the centuries and due to it letting European powers gain control over colonies and not interfering with heir politics, it was surpassed as a dominant force in global politics.