Deterioration, détente, the Thaw?
Well the main countries of East Asia is China and Japan. But unlike China Japan industrialized in less than 50 years, while China was more of an imperial colony for the West nations (West Europe). So China didn't industrialize till 20th Century while Japan industrialized in 19th Century during the 2nd part of Industrial Revolution. So perhaps you can write something about that. And an effect on their Industrialization was Japan became a world power seeking and achieving to get colonies just like the West nations and China gave natural resources for the industrial countries.
The answer is A. Ethnic groups
