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 response captures the historical context in which both Korea and China contributed to Japan's economic practices, especially during different periods. Korea played a significant role in Japan's early development, particularly in transmitting cultural and technological influences, while China had a more substantial impact during the later periods with its advanced political and economic systems.