In this task, you will be presented with a passage and have to answer a question based on your understanding of the events inferred from the passage. Try to find the best answer that is most likely to fill in "_". Note that the URLs in the text have been replaced with [Link].

[EX Q]: (CNN) A submarine is joining the Mediterranean Sea search for the black boxes that could reveal what caused the crash of EgyptAir Flight 804. The aircraft disappeared from radar last week on a flight from Paris to Cairo. Searchers have recovered parts of the plane wreckage, including passengers' personal belongings, life vests, aircraft chairs and even body parts. But they're still scouring the Mediterranean for the plane's fuselage, and for the flight data recorder and cockpit voice recorder -- key pieces of evidence that would likely reveal what went wrong on the flight. Egyptian President Abdel Fattah el-Sisi announced the deployment of the submarine Sunday. It can reach a depth of 3,000 meters (about 9,800 feet), he said.Mourners at a Cairo mosque gather in memory of the plane's pilotEgypt uses submarine to hunt for flight data and cockpit voice recorders 
 Question:The jet had routine maintenance checks in _ before it left for Paris, the airline said.
[EX A]: Cairo

[EX Q]: (CNN) Khuram Shahzad Butt, a 27-year-old British national born in Pakistan who died in a hail of police bullets Saturday night after the London attack, was a tall, lanky, straggly bearded young man of few words -- a brainwashed follower of al-Muhajiroun, a loose grouping of British extremists supportive of ISIS linked to a large number of terrorist plots involving UK nationals. The latest on London attack CNN's Sandi Sidhu met him several times while reporting on the group in the United Kingdom between 2014 and 2016. He went by the name "Abz" or "Abu Zaitun" and seldom spoke during meetings. He was content to leave the task of proselytizing to louder, older members of the group, according to Sidhu.London attacker Khuram Shahzad Butt appeared in a 2016 Channel 4 documentary called "The Jihadis Next Door"At the time of the attack, Butt worked as a receptionist at a fitness center in Ilford, a friend from the gym said 
 Question:The identification of Butt as one of the attackers raised many questions about what _ authorities knew about him and when.
[EX A]: British

[EX Q]: Kiev, Ukraine (CNN) -- Ukraine's President Viktor Yanukovych will return to work on Monday, after taking ill amid political unrest that has paralyzed the eastern European country. Yanukovych went on sick leave on Thursday with "acute respiratory disease," his office said. He is now feeling "good" after treatment and his condition has been assessed as "satisfactory," a statement on the presidential website said. Ukraine has been plunged into a deep political crisis that in the last week saw the Prime Minister and Cabinet resign, a controversial anti-protest law repealed, and the President signing off on a contested amnesty bill for anti-government protesters.Yanukovych is said to be feeling good after treatmentYanukovych went on sick leave Thursday with "acute respiratory disease"Thousands of protesters remain out in Kiev streets on SundayUkraine rattled by protests, then clashes, since November 
 Question:Despite concessions last week from _, including repeal of the controversial law, Ukraine's opposition parties continue to call for constitutional reforms to shift power away from the president.
[EX A]:
Viktor Yanukovych