Today, the clear wrong answer here is number 5. It would be extremely unlikely for a historian in today's world to say that non-western cultures are inherently submissive. This is something that would have been said at the height of imperialism, but not today.
At the height of imperialism, Europeans believed in their racial superiority and the idea that other peoples were submissive. Today, however, we tend to explain European dominance through more tangible and less ethnocentric factors.
The only other possible answer here is number 2. It is hard to define exactly what "cultural dominance" means. However, there are ways to construe this that would make it acceptable to today's scholars. Number 5, by contrast, cannot be made acceptable to current scholarship. Therefore, it is the correct answer--the one that is NOT a basis for European dominance.