To be honest, I would say that all these answers could the right one, but if I had to choose one, I would say that the answer is B: It allows propaganda to reach more people.
Explanation:
If this is wrong, I am sorry. I think this because you could almost fit A and B together, but you could also fit C and D together, but in the total context, social media targets people. It catches their attention. So I went with the answer that included people as a whole.
