In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

Iannis Xenakis used eight so-called "sound complexes" in a solo work for this instrument called Nomos Alpha. Six beats on the body of these instruments begin the main theme in Arvo Part's orchestration of Fratres for twelve of them. An ensemble consisting entirely of these instruments was founded in the 1970s by twelve members of the Berlin Philharmonic. The first of Villa-Lobos's Bachianas Brasileiras was composed for (*) eight of these instruments, while Jacqueline du Pre popularized Edward Elgar's concerto for it. J.S. Bach's six unaccompanied suites for this instrument were famously recorded by both Mstislav Rostropovich and Pablo Casals. For 10 points, name this instrument played by Yo-Yo Ma which joins two violins and a viola in a string quartet.
Fine Arts

One author from this country wrote about a nave village boy recruited to fight in a civil war in his "novel in rotten English," Sozaboy. Another author from this country was awarded the 1991 Booker Prize for his best known work, The Famished Road. Another novel by an author from this nation is No Longer at Ease, which recounts the firing of a government worker, Obi Okonkwo, whose similarly named grandfather was the protagonist of the novel Things Fall Apart. For 10 points, name this nation of Ken Saro-Wiwa, Ben Okri and Chinua Achebe.
Literature

In studying this structure, Elizabeth Gould showed that dendrite spine density and estradiol levels peaked together. A circuit of structures interconnecting this structure and the cortex was proposed by James Papez, and axon collaterals named for Schaffer innervates neurons in the CA1 portion of this structure. Neurons that respond only when an animal is in a certain region of space, known as place cells, are located in this structure. It consists of two sheets of neurons called Ammon's horn and the dentate gyrus, the first of which sends axons into the fornix. Connected ventrally and laterally to the olfactory cortex, this structure inhibits CRH release. For 10 points, name folded structure of the limbic system that plays a major role in learning and memory.

Science