Given the task definition, example input & output, solve the new input case.
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.
Example: Passage: The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. The war was fought between the colonies of British America and New France, with both sides supported by military units from their parent countries of Great Britain and France, as well as Native American allies. At the start of the war, the French North American colonies had a population of roughly 60,000 European settlers, compared with 2 million in the British North American colonies. The outnumbered French particularly depended on the Indians. Long in conflict, the metropole nations declared war on each other in 1756, escalating the war from a regional affair into an intercontinental conflict.
Output: When was the French and Indian War?
This question is based on the following sentence in the passage- The French and Indian War (17541763) was the North American theater of the worldwide Seven Years' War. It is a common convention to write (start year-end year) beside a historical event to understand when the event happened. You can ask questions like this one about dates, years, other numerals, persons, locations, noun phrases, verb phrases, adjectives, clauses etc. which exist in the paragraph.

New input case for you: The fourth Digimon series, which began airing on April 7, 2002, radically departs from the previous three by focusing on a new and very different kind of evolution, Spirit Evolution, in which the human characters use their D-Tectors (this series' Digivice) to transform themselves into special Digimon called Legendary Warriors, detracting from the customary formula of having digital partners. After receiving unusual phone messages from Ophanimon (one of the three ruling Digimon alongside Seraphimon and Cherubimon) Takuya Kanbara, Koji Minamoto, Junpei Shibayama, Zoe Orimoto, Tommy Himi, and Koichi Kimura go to a subway station and take a train to the Digital World. Summoned by Ophanimon, the Digidestined realize that they must find the ten legendary spirits and stop the forces of Cherubimon from physically destroying the Digital World. After finding the ten spirits of the Legendary Warriors and defeating Mercurymon, Grumblemon, Ranamon, and Arbormon, they finally end up fighting Cherubimon hoping to foil his effort to dominate the Digital World. After the defeat of Cherubimon, the Digidestined find they must face an even greater challenge as they try to stop the Royal KnightsDynasmon and Crusadermonfrom destroying the Digital World and using the collected data to revive the original ruler of the Digital World: the tyrannical Lucemon. Ultimately the Digidestined fail in preventing Lucemon from reawakening but they do manage to prevent him from escaping into the Real World. In the final battle, all of the legendary spirits the digidestined have collected thus far merge and create Susanoomon. With this new form, the digidestined are able to effectively defeat Lucemon and save the Digital World. In general, Frontier has a much lighter tone than that of Tamers, yet remains darker than Adventure and Adventure 02.
Output:
When did the fourth series of Digimon begin?