Answer:
You didn't give us the choices but I can try to help.
Before the 19th century, imperialism consisted of mostly colonizing and taking advantage of an area's resources and people for gain. This changed in the 19th century since Imperialism became a larger focus of increasing the size of a country, where instead of simply taking advantage, the colonies were treated as small extensions of countries where the mainland would benefit from the trade and spread of their ideologies.
So basically, global competition between countries in imperialism and spread of influence increased drastically, and I think can be argued as one of the reasons why we had WW1 in the first part of the 20th century. The competition for the best country and empire became a global one instead of being treated as a way to simply get resources, and more about extending reach as well.