What is the main reason for the acquisition of southeast asian colonies by european nations?

The Europeans wanted to establish their prowess over the southeast Asian lands, and that, was for a number of reasons.

Explanation:

The Europeans believed that it is their duty to civilize masses, promote and inculcate Christian values and convert the other regions of the world into capitalist democracies. The Europeans already looked at Southeast Asia as a land of uncivilized population. That being one reason behind the European acquisition of Southeast Asia, the other reason was that the Europeans always wanted to have control over the southeast Asian region because they were aware of the abundance of industrial raw material in the region. They also wanted to set up their colonies in Southeast Asia.

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser 

It is the second answer