The correct option is D It stretches for a distance of 5000 km.
As we move south of the Sahara desert, we can find a narrow band of semi-arid land. This band of land is called the Sahel. The Sahel means border or margin. This narrow band of semi-arid landforms a transition zone between the Sahara in the north and the south's Savanna grasslands. The barren, sandy, and rocky Sahel region covers an area of 3.0 million sq. km. It stretches for a distance of almost 5000 km from east to west. This area marks a physical and cultural shift from a desert north to a tropical grassland in the south.