instruction:
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.
question:
Classical India refers to the period when much of the Indian subcontinent was reunited under the Gupta Empire (c. 320550 CE). This period has been called the Golden Age of India and was marked by extensive achievements in science, technology, engineering, art, dialectic, literature, logic, mathematics, astronomy, religion, and philosophy that crystallized the elements of what is generally known as Hindu culture. The Hindu-Arabic numerals, a positional numeral system, originated in India and was later transmitted to the West through the Arabs. Early Hindu numerals had only nine symbols, until 600 to 800 CE, when a symbol for zero was developed for the numeral system. The peace and prosperity created under leadership of Guptas enabled the pursuit of scientific and artistic endeavors in India.
answer:
By what is India under the Gupta Empire referered?

question:
Prior Zelda games have employed a theme of two separate, yet connected, worlds. In A Link to the Past, Link travels between a "Light World" and a "Dark World"; in Ocarina of Time, as well as in Oracle of Ages, Link travels between two different time periods. The Zelda team sought to reuse this motif in the series' latest installment. It was suggested that Link transform into a wolf, much like he metamorphoses into a rabbit in the Dark World of A Link to the Past.[m] The story of the game was created by Aonuma, and later underwent several changes by scenario writers Mitsuhiro Takano and Aya Kyogoku. Takano created the script for the story scenes, while Kyogoku and Takayuki Ikkaku handled the actual in-game script. Aonuma left his team working on the new idea while he directed The Minish Cap for the Game Boy Advance. When he returned, he found the Twilight Princess team struggling. Emphasis on the parallel worlds and the wolf transformation had made Link's character unbelievable. Aonuma also felt the gameplay lacked the caliber of innovation found in Phantom Hourglass, which was being developed with touch controls for the Nintendo DS. At the same time, the Wii was under development with the code name "Revolution". Miyamoto thought that the Revolution's pointing device, the Wii Remote, was well suited for aiming arrows in Zelda, and suggested that Aonuma consider using it.[n]
answer:
What does Link morph into in A Link to the Past?

question:
By 390 BC, several Gallic tribes were invading Italy from the north as their culture expanded throughout Europe. The Romans were alerted to this when a particularly warlike tribe invaded two Etruscan towns close to Rome's sphere of influence. These towns, overwhelmed by the enemy's numbers and ferocity, called on Rome for help. The Romans met the Gauls in pitched battle at the Battle of Allia River around 390387 BC. The Gauls, led by chieftain Brennus, defeated the Roman army of approximately 15,000 troops, pursued the fleeing Romans back to Rome, and sacked the city before being either driven off or bought off. Romans and Gauls continued to war intermittently in Italy for more than two centuries.[relevant? discuss]
answer:
When did the Battle of Allia River approximately end?