The correct answer is option 3: Sahara. The Sahara Desert is the largest desert in the world, covering an area of approximately 3.6 million square miles. It is located in North Africa, spanning across several countries including Algeria, Chad, Egypt, Libya, Mali, Mauritania, Niger, Sudan, and Tunisia. The Sahara is known for its vast expanse of sand dunes, rocky plateaus, and arid climate with very little rainfall. Despite its harsh conditions, the Sahara is home to a diverse range of plants and animals that have adapted to survive in this extreme environment. The Arabian Desert (option 1) is the second-largest desert in the world, covering parts of Saudi Arabia, Yemen, Oman, and the United Arab Emirates. The Kalahari Desert (option 2) is a large semi-arid sandy savannah located in Southern Africa, and the Thar Desert (option 4) is a desert region in the northwestern part of the Indian subcontinent.