The correct answer is: A. the Sahara desert.
The Sahara desert is the largest hot desert in the world, covering 9,200,000 square kilometers (3,500,000 square miles) in North Africa. It is also the hottest desert on Earth, with average temperatures ranging from 27°C (81°F) in the winter to 37°C (99°F) in the summer. The Sahara is home to a variety of sand dunes, including the highest sand dunes in the world, which can reach heights of over 180 meters (590 feet).
The Atacama desert is the driest desert in the world, located in South America. It is also the second-largest desert in the world, covering 1,050,000 square kilometers (406,000 square miles). The Atacama is home to a variety of sand dunes, but they are not as high as those found in the Sahara desert.
The Kalahari desert is a semi-arid desert located in Southern Africa. It is the third-largest desert in the world, covering 900,000 square kilometers (350,000 square miles). The Kalahari is home to a variety of sand dunes, but they are not as high as those found in the Sahara desert or the Atacama desert.
The Gobi desert is a cold desert located in Central Asia. It is the fifth-largest desert in the world, covering 1,300,000 square kilometers (500,000 square miles). The Gobi is home to a variety of sand dunes, but they are not as high as those found in the Sahara desert, the Atacama desert, or the Kalahari desert.