which statement best describes lake tanganyika?
a) spanning more than 3,200 square miles, it is the largest lake in the world.
b) it is important to the population of nigeria as a source of drinking water.
c) it is the deepest lake in africa and holds the longest freshwater in the world. d) it is the largest lake in africa, approximately twice the size of lake victoria.

I'd say
C) It is the deepest lake in Africa and holds the longest freshwater in the world. 

A is incorrect, it spans 12,703 square miles and is not the largest in the world.
B is incorrect, as Lake Tanganyika and Nigeria are 2869 km apart, and they simply don't rely on it.
C is correct, as it is the deepest lake in Africa and is the longest freshwater source in the world.
D is incorrect, since Lake Victoria is more than half the size of Lake Tanganyika.
So the answer is C. It is the deepest lake in Africa and holds the longest freshwater in the world.