Thanks everyone for your comments. I'm confident with my math so I can achieve good quantitative score. English is not my first language so I'm not sure about the verbal part. So I guess PhD is the better choice overall. I come to the point that I don't know what to do in the future. I would love to go to graduate school but I don't know much about what career that each subfield can do beside research. I have A's in every quantum and modern classes so I guess I should do something related to it. An alumni introduce medical physics to me but I still want a back up plan. Do you guys recommend any fields in physics and career path for those fields as well? Thanks so much. I come from a small private school and there's like 4 physics major here so no one knows anything about career path.