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

[Q]: Tibet's incursions into Sichuan can be classified as what during the Tang Dynasty?, Context: Sichuan came under the firm control of a Chinese central government during the Sui dynasty, but it was during the subsequent Tang dynasty where Sichuan regained its previous political and cultural prominence for which it was known during the Han. Chengdu became nationally known as a supplier of armies and the home of Du Fu, who is sometimes called China's greatest poet. During the An Lushan Rebellion (755-763), Emperor Xuanzong of Tang fled from Chang'an to Sichuan. The region was torn by constant warfare and economic distress as it was besieged by the Tibetan Empire.
[A]: constant


[Q]: 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."
[A]: gut


[Q]: What were the ideals built on?, Context: The Republic of Letters was the sum of a number of Enlightenment ideals: an egalitarian realm governed by knowledge that could act across political boundaries and rival state power. It was a forum that supported "free public examination of questions regarding religion or legislation". Immanuel Kant considered written communication essential to his conception of the public sphere; once everyone was a part of the "reading public", then society could be said to be enlightened. The people who participated in the Republic of Letters, such as Diderot and Voltaire, are frequently known today as important Enlightenment figures. Indeed, the men who wrote Diderot's Encyclopédie arguably formed a microcosm of the larger "republic".
[A]:
knowledge