Answer:
b. It is a series of islands
Step-by-step explanation:
The fact that Japan consists of a series of islands is the main factor why the country has remained in relative isolation. Although Japan had some early contact with the cultures of China and Korea, this contact was very limited, and for much of its history, Japan remained quite isolated. When the West wanted to establish trade with the nation, Japan was originally quite reluctant. However, Japan was eventually forced to open its borders and engage in international trade during the 19th century.