Identify the author of "No Longer at Ease," a novel addressing post-colonial themes.

The correct author of "No Longer at Ease" is Chinua Achebe. This novel, first published in 1960, serves as a sequel to Achebe's earlier work, "Things Fall Apart." It delves into the complexities of post-colonial Nigeria, exploring the challenges faced by individuals who navigate the tensions between traditional values and the newly imposed Western influences following independence. Achebe's narrative style and character development effectively highlight the struggles of his protagonist, Obi Okonkwo, as he attempts to reconcile his education abroad with his roots in Nigerian culture.

In addition to Achebe, the other authors listed are notable in their own right. Wole Soyinka, for instance, is known for his plays and poetry that also address themes of colonialism and identity, while Nadine Gordimer and Ayi Kwei Armah have contributed significant works exploring socio-political issues in their respective regions. However, when it comes to "No Longer at Ease," it is specifically Achebe who engaged deeply with the subject matter of post-colonial realities in this particular novel.