First of all, please look for parallelism.
a lowering of interest rates, a rally in stocks and bonds and a weakening of the dollar.
Now, the choice boils down to B and C. C is awkward because of a comma(,) and along with fears. When you are using a comma, you are separating them into two separate clauses completely, which is not desired.
Probably, you can get the BEST explanation from OG. I could explain in my best words
I didn't touch OG from 2 weeks:-)