The longest border between any two countries in the world is between:

(a) Canada and the United States of America
(b) Chile and Argentina
(c) China and India
(d) Kazakhstan and Russian Federation

Correct Answer:
(a) Canada and the United States of America

Explanation:

The longest border between any two countries in the world is between Canada and the United States of America. This border stretches for 8,893 kilometers.

Dealing with All Options:

Option (a): Canada and the United States of America
- The Canada–United States border is the longest international border in the world, measuring 8,893 kilometers.
Option (b): Chile and Argentina
- The Argentina–Chile border is the longest international border in South America and the third longest in the world, measuring 5,308 kilometers.
Option (c): China and India
- The China–India border, also known as the Line of Actual Control, measures 3,380 kilometers and is not among the longest borders in the world .
Option (d): Kazakhstan and Russian Federation
- The Kazakhstan–Russia border is the second longest international border in the world, measuring 7,644 kilometers.

Canada–United States Border:
- Length: 8,893 kilometers.
- Characteristics: It includes the border between Canada and the contiguous United States and the border between Canada and Alaska.
- Management: The International Boundary Commission and the International Joint Commission handle boundary marking and water issues, respectively .
Kazakhstan–Russia Border:
- Length: 7,644 kilometers.
- Characteristics: It is the longest continuous international border in the world.
- Geography: Runs from the Caspian Sea to the tripoint with China, traversing the Eurasian Steppe and Altai Mountains .
Argentina–Chile Border:
- Length: 5,308 kilometers.
- Characteristics: Runs along the Andes and on the islands of Tierra del Fuego.
- Disputes: There are some border disputes, particularly around the Southern Patagonian Ice Field .
China–India Border:
- Length: 3,380 kilometers.
- Characteristics: Known as the Line of Actual Control, it is a notional demarcation line separating Indian-controlled territory from Chinese-controlled territory.
- Disputes: The border is a major point of contention between the two countries, with several skirmishes and ongoing disputes .