The correct answer is option 'B'. The Amazon Basin is indeed the largest river basin in the world. Let's explore the reasons behind this answer in detail.

The Amazon Basin: Overview
The Amazon Basin is a vast region in South America that encompasses the drainage basin of the Amazon River and its tributaries. It covers an area of approximately 7 million square kilometers, making it the largest river basin in the world.

Size and Geography
The Amazon Basin spans across several countries in South America, including Brazil, Peru, Colombia, Venezuela, Ecuador, Bolivia, Guyana, and Suriname. It is primarily located in Brazil, where the majority of the Amazon Rainforest, often referred to as the "lungs of the Earth," is situated.

The Amazon River
The Amazon River, which originates in the Andes Mountains of Peru, is the largest river by discharge volume in the world. It has a length of approximately 6,400 kilometers, making it the second-longest river globally, after the Nile. The Amazon River and its countless tributaries flow through the Amazon Basin, forming an intricate network of waterways.

Importance and Biodiversity
The Amazon Basin is of immense ecological importance and is home to the greatest biodiversity on the planet. The Amazon Rainforest, which covers a significant portion of the basin, is teeming with diverse plant and animal species, many of which are endemic to the region. This rich biodiversity contributes to the overall health of the planet and provides numerous ecosystem services.

Human Impact
The Amazon Basin is facing various environmental challenges due to human activities such as deforestation, illegal logging, mining, and agriculture. These activities not only threaten the delicate balance of the ecosystem but also have global implications, including climate change and loss of biodiversity.

Conclusion
In conclusion, the Amazon Basin is the largest river basin in the world, covering a vast area in South America and serving as the home to the Amazon River and its tributaries. Its immense size, ecological importance, and rich biodiversity make it a unique and significant region on our planet.

The correct option is world