​Cultural evolution is best defined as:

A) ​cultural change over time
B) ​a process of cultural progress over time
C) ​a mode of production that becomes more complex over time
D) ​adaption to biological and cultural change

Cultural evolution refers to the changes in cultural traits or patterns that occur over time. It is a process of cultural change that often results from interactions between different groups or due to environmental factors. It does not necessarily imply progress or improvement, and it can occur in any direction. Therefore, option A is the most appropriate definition of cultural evolution.