In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

what type of string is mentioned third to last?, Context: Samuel Adelstein described the Lombardi mandolin in 1893 as wider and shorter than the Neapolitan mandolin, with a shallower back and a shorter and wider neck, with six single strings to the regular mandolin's set of 4. The Lombardi was tuned C, D, A, E, B, G. The strings were fastened to the bridge like a guitar's. There were 20 frets, covering three octaves, with an additional 5 notes. When Adelstein wrote, there were no nylon strings, and the gut and single strings "do not vibrate so clearly and sweetly as the double steel string of the Neapolitan."
gut

What does the S in "OAS" stand for?, Context: Further conventions were adopted at the regional level under the aegis of the Organization of American States (OAS or OEA), the African Union, and in 2003, at the universal level under that of the United Nations Convention against Corruption.
States

Foedus is a?, Context: The terms 'federalism' and 'confederalism' both have a root in the Latin word foedus, meaning treaty, pact or covenant. Their common meaning until the late eighteenth century was a simple league or inter-governmental relationship among sovereign states based upon a treaty. They were therefore initially synonyms. It was in this sense that James Madison in Federalist 39 had referred to the new United States as 'neither a national nor a federal Constitution, but a composition of both' (ie. neither a single large unitary state nor a league/confederation among several small states, but a hybrid of the two). In the course of the nineteenth century the meaning of federalism would come to shift, strengthening to refer uniquely to the novel compound political form, while the meaning of confederalism would remain at a league of states. Thus, this article relates to the modern usage of the word 'federalism'.
Latin word