Why did Japan expand into Southeast Asia?

Between the late 19th century and the early 20th century, Japan underwent rapid industrialization. In order to keep expanding, it needed control of more resources, more raw materials for its industries, and also new markets for Japanese products. Taking advantage of its superior economic  and technological might, and of its military superiority, Japan followed a progressive policy of conquest and territorial expansion: Taiwan , Korea, Manchuria , coastal China, Southeast Asia. The oil, rubber and foodstuff from Southeast Asia were also necessary for the operation of its armed forces once WWII started.

Explanation:

b - those executed came from every social and economic class