How do I choose my research area?
If you have a relatively open set of research interests, I would focus much more on finding an advisor who you believe you will get along well with on a personal level. "Success" (which is admittedly an ambiguous term) in a PhD often matters much less on what you are studying specifically and much more on how engaged and dedicated you are to the research process as a whole. It is very difficult to be engaged in research on a topic you love, but with an advisor you despise. 

I would not be too worried about getting trapped in a certain research field long term. You doctoral work is a relatively short portion of your research career as a whole. I have already changed my research focus twice in my career (MS was one topic, PhD was another, full-time employment is yet another). And I still have three plus decades of research to go (so my research career is still young). I did what work my advisor was interested in, put my own flavor into it, then changed my focus as necessary in  my employment.   

As for your research making an impact, understand that very, very, very few doctoral researchers make a ground breaking impact as a PhD student. Most PhD researchers go their whole career in fact and only impact "a very small slice of the pie." That is how research is modernly. You can make an impact in any of the research fields you listed. Don't sell yourself short of course, but also be aware that most people with PhDs do not in and of themselves change the world.