Answer is D, The Nigeria savanna vegetation include Sudan,Sahel and guinea.

Sudan savanna comes immediately after the north of the guinea savanna as the cardinal point on the diagram describes the direction to the north, the Sudan comes after the guinea the chief product are cattle, groundnut, guinea corn and millet The Sahel savanna is made up of grasses and water shortage is experienced there and this does not encourage plant to grow luxuriantly.

The guinea savanna is suitable between Sudan savanna and rain forest