The correct answer is C: Naruhito. Emperor Naruhito of Japan officially inaugurated the Tokyo 2020 Olympic Games (which were postponed and held in July 2021 due to the COVID-19 pandemic). As the reigning monarch and head of state, it is a traditional role for the Emperor of the host country to declare the Olympic Games open. His address marked the formal commencement of the global sporting event amidst unprecedented circumstances.
Option A: Akihito is incorrect. Akihito is the former Emperor of Japan and Naruhito's father. He abdicated the Chrysanthemum Throne in April 2019, well before the scheduled (and then postponed) Tokyo Olympics. Therefore, he was not the reigning monarch at the time of the inauguration.
Option B: Fumio Kishida is incorrect. Fumio Kishida became the Prime Minister of Japan in October 2021, which was after the Tokyo Olympics had concluded. While the Prime Minister is the head of government, the role of inaugurating the Olympics falls to the head of state, which is the Emperor.
Option D: Shinzo Abe is incorrect. Shinzo Abe was the Prime Minister of Japan when Tokyo won the bid for the 2020 Olympics and during much of the preparation phase. However, he resigned as Prime Minister in September 2020, prior to the delayed Games in 2021. Even if he had still been in office, the official inauguration duties typically rest with the Emperor.