The response that best describes how the materials used by Olmec artists reflect the complexity and level of development of Olmec culture is:
They used materials that originated from long distances and were difficult to work with.
This response highlights the Olmec's ability to trade and acquire materials from afar, indicating a level of sophistication in their society related to trade networks, resource management, and artistic skills. Using materials that are challenging to work with also points to advanced techniques and a deep understanding of their chosen mediums.