In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: Which person involved in the sale of the southern coast of Namibia is the oldest? Passage:German Namibians () are a community of people descended from ethnic German colonists who settled in present-day Namibia. In 1883, the German trader Adolf Luderitz bought what would become the southern coast of Namibia from Josef Frederiks II, a chief of the local Oorlam people, and founded the city of Luderitz. The German government, eager to gain overseas possessions, annexed the territory soon after, proclaiming it German South West Africa (). Small numbers of Germans subsequently immigrated there, many coming as soldiers (), traders, diamond miners, or colonial officials. In 1915, during the course of World War I, Germany lost its colonial possessions, including South West Africa (see History of Namibia); after the war, the former German colony was administered as a South African mandate. The German settlers were allowed to remain and, until independence in 1990, German remained an official language of the territory alongside Afrikaans and English.
Links: a. World War I b. Adolf Luderitz c. Josef Frederiks II d. Afrikaans
b