Answer:
The correct answer is: more branches will appear as new churches are founded.
Step-by-step explanation:
This is likely to happen to Christianity in the future because it is the natural course of evolution. The new inhabitants of the world will have a broader scope thanks to the findings and studies of the ones that came before them. So, new branches with new concepts and understandings are likely to appear.
It is not likely to become an ethnic religion since the number of adherents throughout the world is huge, and they are not likely to halt (stop) their missionary practices either since their goal is to draw more people towards them. Divisions between branches are not likely to diminish since every branch holds on to their specific set of beliefs.