Final answer:
Tokyo has the highest percentage of its population aged 65 or older.
Step-by-step explanation:
The country with the highest percentage of its population aged 65 or older among the given options is A. Tokyo. According to the information provided, Japan, and specifically Tokyo, has a rapidly aging population. By 2050, nearly a third of the Chinese population will be age sixty or older, which puts a significant burden on the labor force and impacts China's economic growth.