Oral tradition refers to the transmission of cultural knowledge, history, customs, stories, and beliefs from one generation to the next through spoken word rather than written records. It is most useful in reconstructing the history of pre-literate African societies - communities that did not develop or widely use writing systems to record their past.
Before the arrival of Islam (which brought Arabic script) and European colonialism (which brought Latin script) to many parts of Africa, most African societies had no indigenous writing systems. Their histories, genealogies, laws, and cultural practices were preserved and transmitted orally by designated keepers of tradition, such as griots in West Africa. These oral accounts provide invaluable evidence about the political organisation, migrations, wars, social structures, and religious practices of these societies.
While oral tradition can supplement written records for more recent periods, it is not the primary or most useful source for reconstructing recent wars, church history, or colonial administration. These topics are far better served by written documents, official records, treaties, correspondence, and archival materials that exist in abundance. It is precisely in the absence of such written records - as in pre-literate African societies - that oral tradition becomes the most important and sometimes the only available source of historical knowledge.
The correct answer is pre-literate African societies, for which oral tradition is the most essential tool of historical reconstruction.