I dont think body odor ever played an evolutionary role. As far as I know body odor is caused by bacterias eating and multiplying whenever we sweat. If this is the case body odor is here because we sweat which isnt that common within the animal kingdom.
(Although dont quote me on any of this, this is just what I seem to remember and Im lazy to look it up - tldr i might be lying)
I am unfamiliar with your school system I think. Final year of college / university? Do you have a specialization in your major (graphics, machine learning, embedded, networks / security - something like this?)
I’d go with something from the specialization if you have one. If not, just something that interests you.