Chinua Achebe was a Nigerian novelist. He had a title of chieftain of Igbo tribe and wrote novels about its customs. That was portrayed as sophisticated, passed down through generations.
Westerners may mistaken them as ‘primitive and savage’. But Achebe showed Igbo people's rich cultural background through his narrations. Igbo proverbs, ‘the art of conversation", were frequently quoted in his novels.
The non-violent nature of Igbo was demonstrated by events like the peaceful agreement with the Mbaino tribe during a murder in Igbo by a Mbaino man.
The answer to your question is,
D. A repeated sound within a line of poetry.
-Mabel <3
