Answer: A. viewpoint.
This excerpt is an example of a viewpoint because it presents the perspective and personal view of the author. He claims that the drum is an enduring document of the geopolitical fault-line around the Nile cataracts. He also argues that the drum is part of the history of African indigenous culture and the European Scramble for Africa. Both of these statements display his own analysis. The passage does not summarize previous information, adds explanatory details or acts as a source.