Step 1: Understanding the question.
The question asks about the host country of the Asian Games held in 2023.
Step 2: Analyzing the options.
(A) Japan: Japan hosted earlier editions, not 2023.
(B) South Korea: Hosted in previous years, not 2023.
(C) China: Correct — China hosted the Asian Games 2023 in Hangzhou.
(D) Indonesia: Hosted the 2018 Asian Games.
Step 3: Conclusion.
The Asian Games 2023 were hosted by China.