The response that best describes how both Korea and China influenced the development of Japan’s economic system is: Korea had an important influence on the ancient Japanese economy, but, later on, China was more influential.
This reflects the historical context where Korea played a significant role in introducing various technologies and cultural practices to Japan in its early development, while later, China had a more profound influence on Japan's political, economic, and cultural systems, particularly during periods such as the Tang and Song Dynasties.