The Nile River is the longest river in the world at 6650km long. The Amazon River is a close second at 6400km.
The Nile River is traditionally considered the longest river in the world at approximately 6,650 kilometers long, while the Amazon River is about 6,400 kilometers long. The exact measurements can vary due to modern technologies, leading to some debate between the two rivers for the title of longest river. Therefore, the correct answer is A. Nile.
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