The most accurate response to describe the impact of decolonization worldwide after World War II would be:
"In the decades after World War II, many empires granted independence to their former global colonies. This caused the birth of new countries worldwide. This process occurred peacefully in some places and violently in many places."
This response captures the essence of the decolonization movement, recognizing both the peaceful and violent transitions to independence and the significant geopolitical changes that followed, including the establishment of new nations.