Which is a good example of specifying with a question when looking for a good research topic?

A. What should we do about global warming?
B. I wonder what we should do to help end global
warming.
C. What are some good examples of good results
that help end global warming?
D. How is the melting of sea ice impacting polar
bears in the Arctic Circle?

D. How is the melting of sea ice impacting polar bears in the Arctic Circle?