Step 1: Understanding the question.
The question asks about the country that built its first domestically developed (homegrown) cruise ship named Adora Magic City.
Step 2: Analyzing the options.
(A) Japan: Japan has a strong shipbuilding industry but Adora Magic City is not Japanese.
(B) South Korea: South Korea is a major shipbuilder, but this ship does not belong to it.
(C) China: Correct — Adora Magic City is China’s first domestically built large cruise ship.
(D) Singapore: Singapore is a major port hub, not the builder of this ship.
Step 3: Conclusion.
Adora Magic City is the first homegrown cruise ship of China.