Racism isnt specific - it's very broad in my opinion and I think it would be good idea to do that instead of social issues as that's very very broad. If you want to do racism, defo go for it but if you are unsure, choose social issues as you could experiment with different themes then zoom into a specific area such as racism for your development for your final project. Maybe talk about what you are planning to do with the topic, what you want to convey through your work and what you want to achieve at the end.