The correct answer is (b). T. Kajita is from Japan and A. McDonald is from the United States.
Takaaki Kajita is a Japanese particle physicist who shared the 2015 Nobel Prize in Physics with Arthur B. McDonald for their discovery of neutrino oscillations, which shows that neutrinos have mass. He is a professor at the University of Tokyo and a member of the Japan Academy.
Arthur Bruce McDonald is a Canadian physicist who shared the 2015 Nobel Prize in Physics with Takaaki Kajita for their discovery of neutrino oscillations. He is a professor emeritus at
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