Step 1: The Asian Infrastructure Investment Bank (AIIB) is a multilateral development bank that focuses on infrastructure development in Asia.
Step 2: AIIB's headquarters is located in Beijing, China.
Step 3: Therefore, the correct answer is option (c) China. \[ \boxed{\text{China}} \]
The location of an international bank's headquarters is usually tied to the country that championed its formation, so each option can be checked against that idea.
Since Beijing houses the AIIB's headquarters, option 3 stands out as correct.
Hence, the correct answer is China.