In Recent Years the Economy of Japan Has Grown, Despite

In recent years the economy of Japan has grown, despite the fact that the population of Japan has declined. Which of the following would best explain Japan's economic growth despite having a smaller population?

A) immigration of new workers into Japan
B) advancements in technology that make labor more productive
C) reduced employment of capital because fewer workers are available to use it
D) greater consumption of goods imported from other countries