Display Ad Campaign - Audience Targetting - Please help me out?

should i take (topic, placements and keywords) all three in one ad campaign ? or i should target only 1 of them?

Campaign 1
Ad Group - Topics
Ad Group - Placements
Ad Group - Keywords

In short, add every targeting in separate ad group if you are targeting in single location. This way you will be able to know which one is performing better.