A.
The correct answer is Tibet, because Tibet is an autonomous region within China, and the Chinese government has significant control over Tibet's political affairs, including its government, economy, and military.
In contrast, Taiwan is a self-governing island nation with its own political system, government, and military, and is not under Chinese political control, although China claims Taiwan as part of its territory.
North Korea is a sovereign state with its own political system, government, and military, and while China is a significant ally and trading partner, North Korea has its own independent political identity and is not under Chinese political control.
So, among the options, Tibet is the one that has its politics established or controlled by China.