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

[Q]: What year, exactly, did the Yongle Emperor take the throne from the Jianwen Emperor?, Context: In his usurpation of the throne from the Jianwen Emperor (r. 1398–1402), the Yongle Emperor was aided by the Buddhist monk Yao Guangxiao, and like his father, the Hongwu Emperor, the Yongle Emperor was "well-disposed towards Buddhism", claims Rossabi. On March 10, 1403, the Yongle Emperor invited Deshin Shekpa, 5th Karmapa Lama (1384–1415), to his court, even though the fourth Karmapa had rejected the invitation of the Hongwu Emperor. A Tibetan translation in the 16th century preserves the letter of the Yongle Emperor, which the Association for Asian Studies notes is polite and complimentary towards the Karmapa. The letter of invitation reads,
[A]: 1402


[Q]: What is one example of hydrogen cations?, Context: To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium ion" (H3O+). However, even in this case, such solvated hydrogen cations are more realistically conceived as being organized into clusters that form species closer to H9O+4. Other oxonium ions are found when water is in acidic solution with other solvents.
[A]: hydronium ion


[Q]: What was the stepping stone that the committees used prior to being effective at a national level?, Context: The People's Committees led to a high percentage of public involvement in decision making, within the limits permitted by the RCC, but exacerbated tribal divisions. They also served as a surveillance system, aiding the security services in locating individuals with views critical of the RCC, leading to the arrest of Ba'athists, Marxists and Islamists. Operating in a pyramid structure, the base form of these Committees were local working groups, who sent elected representatives to the district level, and from there to the national level, divided between the General People's Congress and the General People's Committee. Above these remained Gaddafi and the RCC, who remained responsible for all major decisions.
[A]:
sent elected representatives to the district level