This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Mahayana Buddhism received significant theoretical grounding from Nagarjuna (perhaps c. 150–250 CE), arguably the most influential scholar within the Mahayana tradition. Nagarjuna's primary contribution to Buddhist philosophy was the systematic exposition of the concept of śūnyatā, or "emptiness", widely attested in the Prajñāpāramitā sutras that emerged in his era. The concept of emptiness brings together other key Buddhist doctrines, particularly anatta and dependent origination, to refute the metaphysics of Sarvastivada and Sautrantika (extinct non-Mahayana schools). For Nagarjuna, it is not merely sentient beings that are empty of ātman; all phenomena (dharmas) are without any svabhava (literally "own-nature" or "self-nature"), and thus without any underlying essence; they are "empty" of being independent; thus the heterodox theories of svabhava circulating at the time were refuted on the basis of the doctrines of early Buddhism. Nagarjuna's school of thought is known as the Mādhyamaka. Some of the writings attributed to Nagarjuna made explicit references to Mahayana texts, but his philosophy was argued within the parameters set out by the agamas. He may have arrived at his positions from a desire to achieve a consistent exegesis of the Buddha's doctrine as recorded in the Canon. In the eyes of Nagarjuna the Buddha was not merely a forerunner, but the very founder of the Mādhyamaka system.
Nagarjuna's main contribution was the exposition of the concept of what?

Hans Bielenstein writes that as far back as the Han dynasty (202 BCE–220 CE), the Han Chinese government "maintained the fiction" that the foreign officials administering the various "Dependent States" and oasis city-states of the Western Regions (composed of the Tarim Basin and oasis of Turpan) were true Han representatives due to the Han government's conferral of Chinese seals and seal cords to them.
What was the western regions composed of?

Works of classical repertoire often exhibit complexity in their use of orchestration, counterpoint, harmony, musical development, rhythm, phrasing, texture, and form. Whereas most popular styles are usually written in song forms, classical music is noted for its development of highly sophisticated musical forms, like the concerto, symphony, sonata, and opera.
Works of classical repertoire exhibit what in their use of orchestration and harmony, and form?