The correct answer is C) the Spanish forced Christianity on the Native Americans when they conquered parts of South America.
The best example of cultural diffusion is “the Spanish forced Chrisitianity on the Native Americans when they conquered parts of South America.”
When the Spanish people conquered many regions in South America, they forced the indigenous people to change their old traditions and beliefs systems in order to implement Christianity on them. The cultural diffusion implied to change behaviors that were brought from Spain to change indigenous people minds and ways to think and act. It was not an easy task because the indigenous people never lost its culture and tradition that can be seen nowadays in many places from Mexico, Central, and South America.