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

What was the name of the person who joined in on the coup with Xianfeng's empress?, Context: These years saw an evolution in the participation of Empress Dowager Cixi (Wade–Giles: Tz'u-Hsi) in state affairs. She entered the imperial palace in the 1850s as a concubine to the Xianfeng Emperor (r. 1850–1861) and came to power in 1861 after her five-year-old son, the Tongzhi Emperor ascended the throne. She, the Empress Dowager Ci'an (who had been Xianfeng's empress), and Prince Gong (a son of the Daoguang Emperor), staged a coup that ousted several regents for the boy emperor. Between 1861 and 1873, she and Ci'an served as regents, choosing the reign title "Tongzhi" (ruling together). Following the emperor's death in 1875, Cixi's nephew, the Guangxu Emperor, took the throne, in violation of the dynastic custom that the new emperor be of the next generation, and another regency began. In the spring of 1881, Ci'an suddenly died, aged only forty-three, leaving Cixi as sole regent.
Prince Gong

Which of the following people was highest in status: Princess Marcelina, Thomas Albrecht, or Solange?, Context: Some of his friends provided music at his request; among them, Potocka sang and Franchomme played the cello. Chopin requested that his body be opened after death (for fear of being buried alive) and his heart returned to Warsaw where it rests at the Church of the Holy Cross. He also bequeathed his unfinished notes on a piano tuition method, Projet de méthode, to Alkan for completion. On 17 October, after midnight, the physician leaned over him and asked whether he was suffering greatly. "No longer", he replied. He died a few minutes before two o'clock in the morning. Those present at the deathbed appear to have included his sister Ludwika, Princess Marcelina Czartoryska, Sand's daughter Solange, and his close friend Thomas Albrecht. Later that morning, Solange's husband Clésinger made Chopin's death mask and a cast of his left hand.
Princess Marcelina

What are the things that are necessary for this process to function?, Context: The development of quadraphonic records was announced in 1971. These recorded four separate sound signals. This was achieved on the two stereo channels by electronic matrixing, where the additional channels were combined into the main signal. When the records were played, phase-detection circuits in the amplifiers were able to decode the signals into four separate channels. There were two main systems of matrixed quadraphonic records produced, confusingly named SQ (by CBS) and QS (by Sansui). They proved commercially unsuccessful, but were an important precursor to later surround-sound systems, as seen in SACD and home cinema today.

phase-detection circuits in the amplifiers