One could have training sessions, workshops, and classes in order to help others understand more about different cultures and ethnicities. The more one is exposed to varying nationalities the more likely they will understand that different people are just like them. They could be given material in audio, video, and written format on how different people from around the world behave. Anyone who continues to discriminate should be reprimanded and others should call it out before it gets worse.
The first answer is the only well written thesis statement because it elaborates on the topic more than the others and it provides solid reasons to support its claim.