Going in the 1900s was The Great Depression. Before hand to be dry meant they didn't have many sources which include some of the following (food, supplies, fresh water) They were dry of goods and didn't have much to rely on.
The desert which covers much of Botswana is called the Kalahari Desert.
The speakers of European languages originally emigrated from Egypt. The correct option among all the options that are given in the question is the third option or the last option. There are many theories regarding this immigration. I hope that the answer has come to your help.