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].

Q: We're not bluffing, the Obama administration told Afghanistan on Tuesday in announcing for the first time it has started planning for the possible withdrawal of all U.S. troops by the end of the year if no security agreement is signed. Statements by the White House and Defense Secretary Chuck Hagel showed President Barack Obama's impatience with Afghanistan President Hamid Karzai's refusal to sign the agreement that would keep several thousand American troops in the country after combat operations conclude this year. In a phone call with Karzai on Tuesday to discuss upcoming elections for a new Afghan leader, Obama made clear that time was running out to properly plan for keeping any U.S. forces in the country beyond 2014, the White House said.President Obama calls Afghan leader to discuss security agreementObama orders planning for bringing home all U.S. troops at the end of 2014Afghan President Karzai refuses to sign a deal to keep some troops thereThe White House says an agreement could happen after Karzai leaves office in April 
 Question:Obama, he said, has been very clear that the possibility of U.S. troops staying in Afghanistan depends "on whether we have a bilateral security agreement signed by the Afghani government, to assure our rights of our troops and other important elements that are required any time _ has troops in another country."

A: U.S.
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Q: We've all been frustrated in the airport when a gloating social network update about an impending luxury getaway is cut short by the Wi-Fi cutting out. And businessmen conducting that last-minute conference call throw their arms in the air when mid-conversation, connectivity is lost. However, these may not be common occurrences in Suvarnabhumi Airport in Thailand - as it has the fastest airport Wi-Fi in the world. And a new infographic shows its nearest competitors. Blog website rottenwifi.com tested out speeds at airports around the world, and it was in the Far East where the fastest was discovered recording an impressive 41.45 megabits per second (Mbps).Suvarnabhumi Airport in Thailand has fastest Wi-Fi in the worldDublin Airport comes in third - but no English representatives make the listStudy found fliers only have 'some' chance of Wi-Fi on 24% of flights 
 Question:An infographic was then produced that shows the top 10 best airports for _-Fi speed.

A: Wi
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Q: Romulus, Michigan (CNN) -- Part of an explosive device that failed to take down a plane last week was sewn into the underwear of the Nigerian man accused of igniting it, a law enforcement official told CNN Monday. Umar Farouk AbdulMutallab is being held for allegedly trying to blow up a flight carrying 300 passengers on Christmas Day. Al Qaeda in the Arabian Peninsula claimed responsibility Monday for the attack, saying it was in retaliation for alleged U.S. strikes on Yemeni soil. In a message written in Arabic, dated Saturday and published Monday on radical Islamist Web sites, the group hailed the "brother" who carried out the "heroic attack."Al Qaeda blames "non-complete explosion" on "technical problem"President Obama vows to use "every element" in U.S. arsenal to combat terrorPart of explosive device was sewn into suspect's underwear, official saysAl Qaeda says it tested new explosive that got through security; threatens more attacks 
 Question:According to the ministry's statement, AbdulMutallab had obtained a visa to study _ at a language institute in Yemen where he had previously studied.

A:
Arabic
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