Which of the following countries does not share a land border with China?

Introduction / Context:
China is one of the largest countries in the world and shares its land borders with many neighboring states in Asia. Geography based general knowledge questions frequently ask which country shares or does not share a border with a particular nation. This question checks whether you know the correct list of immediate neighbors of China and can identify the country that is nearby in the region but does not actually touch China's territory.

Given Data / Assumptions:

• We are comparing borders of China with four regional countries: Cambodia, Laos, Vietnam, and Myanmar, plus an extra distractor option.
• We are concerned only with land borders, not maritime boundaries.
• Geographical knowledge of Southeast Asia and East Asia is required.
• No map is provided, so the answer must come from prior learning or mental mapping.

Concept / Approach:
The key concept is to recall which countries physically touch Chinese territory. China shares borders with 14 countries, including Laos, Vietnam, and Myanmar in Southeast Asia. Cambodia is near these states but is separated from China by Laos and Vietnam, so it does not directly meet China. By remembering that China's southern borders involve Myanmar, Laos, and Vietnam, and that Cambodia lies further south, you can logically choose the correct answer even without seeing a map.

Step-by-Step Solution:
Step 1: Recall China's neighbors in Southeast Asia: Myanmar, Laos, and Vietnam definitely share land borders with China. Step 2: Note that Cambodia lies south of Laos and Vietnam and touches Thailand, Vietnam, and the Gulf of Thailand, but not China. Step 3: Cross check each option: Laos borders China, Vietnam borders China, and Myanmar borders China. Step 4: Confirm that Cambodia does not appear in standard lists of China's land neighbors. Step 5: Conclude that Cambodia is the only country in the given set that does not share a land border with China.

Verification / Alternative check:
A quick verification method is to think from north to south along China's southern edge. Starting from the eastern side, you encounter Vietnam, then Laos, and further west Myanmar, all touching Chinese provinces like Yunnan and Guangxi. Cambodia is always described as located south of Laos and Vietnam. Many atlases and exam books present a list of 14 countries bordering China; Cambodia does not appear in that list. This cross check supports the conclusion that Cambodia does not share a land boundary with China.

Why Other Options Are Wrong:
Laos: Laos directly borders China in the south of Yunnan province, and this fact is part of the standard border list of China, so it cannot be the correct answer.
Vietnam: Vietnam shares a land border with China along its northern region, historically important in several conflicts, therefore it is a confirmed neighbor.
Myanmar: Myanmar borders China along Yunnan province, and this border is often mentioned in trade and infrastructure discussions, so it also cannot be correct.
Thailand: Thailand does not border China, but it is not among the original four key options in the question stem, so it serves as an additional distractor only.

Common Pitfalls:
Learners sometimes confuse proximity with a direct border and may think that Cambodia touches China simply because it is in mainland Southeast Asia. Another common mistake is to mix up the relationships of Laos, Cambodia, and Vietnam, especially if one has not visualized the region on a map. To avoid this, remember the rough order from north to south: China, then Laos or Vietnam, and only then Cambodia further south. This mental sequence makes it clear that Cambodia is separated from China by other countries.

Final Answer:
The country among the options that does not share a land border with China is Cambodia.