Which of the following countries is not in North Africa?

North Africa refers to a group of countries and territories occupying the northerly region of the African continent. There is no clear definition of the extent and boundaries of North Africa. It is often defined as the part of Africa stretching from the Atlantic shores in the west to the Red Sea coast and Suez Canal in the east, and including the 6 countries of Morocco, Algeria, Tunisia, Libya, Egypt, and Sudan.

Mauritania, a country in Northwest Africa which has a generally flat landscape with vast plains that are punctuated by the occasional ridge or cliff-like outcropping.

Bisecting the plains in the center of the country is a series of sandstone plateaus giving way to spring-fed oases. The most prominent feature of this region is the Guelb er Richat, also known as the Eye of the Sahara, which is a deeply eroded dome consisting of a variety of intrusive and extrusive igneous rocks.

Three-quarters of the Mauritania landscape is desert or semidesert, and as a result of severe drought, the arid land has been expanding. There are no significant lakes or rivers in the country.