instruction:
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].
question:
(CNN) The cavalry is coming! Not exactly, but the sentiment of reassurance is the same. This week, US Defense Secretary James Mattis arrives in Asia to visit South Korea and Japan. Two stalwart US allies, policymakers in both capitals have nevertheless been shaken by statements Donald Trump made while campaigning for President. None of these was more dramatic than the suggestion that these allies should pay more for US troops or risk having these forces withdrawn. Statements like this played to the worst fears in Seoul and Tokyo that the United States might no longer be a committed ally. It is now Mattis' job to reassure them of US commitments and return the trajectory of alliance relations back to pre-2016 presidential campaign rhetoric.Jeffrey Hornung: Japan, South Korea were shaken by statements Donald Trump made while campaigningWashington's alliances with Seoul and Tokyo will be critical in managing challenges posed by China and North Korea, he says 
 Question:Given the severity of the _ threat, it is crucial they hammer out any possible differences that may have arisen since Trump became president.
answer:
North Korea


question:
The family of schoolgirl Alice Gross have demanded to know how her murderer got into Britain despite killing his wife in his native Latvia. The 14-year-old went missing in August last year and her body was discovered the following month in the Grand Union Canal in Ealing, west London. Her killer Arnis Zalkalns, 41, had been named as a suspect in her disappearance but his body was later found hanging in a woodland nearby. Police later confirmed that the Latvian builder, who had come to the UK in 2007, was responsible, and the CPS announced that he would have been charged with murder if alive.Alice went missing last year and body later found in canal in west LondonThe man suspected of killing her was found hanging in woodland nearbyArnis Zalkalns had been jailed in native Latvia for 7 years for killing his wifeCame to UK in 2007 and in 2009 was arrested on suspicion of sex asault 
 Question:Mr Thacker told the court, that _'s nationality was not the issue here and that Alice's family 'just want answers'.
answer:
Arnis Zalkalns


question:
(CNN) Theranos decided to voluntarily withdraw its Zika virus blood test that it had submitted for Food and Drug Administration approval, the company said Wednesday. Theranos founder and CEO Elizabeth Holmes previously told CNN Chief Medical Correspondent Dr. Sanjay Gupta in an exclusive interview that the Zika test, though it's not one that would be as common as a test to check general health, was a priority for the company because it was a "really important area of blood work." She talked about the test at her first presentation to the American Association for Clinical Chemistry Meeting in August. The hope, she said, was to be able to run the Zika test on a new mini-lab device the company debuted at the conference.The company still considers Zika a "really important area of blood work"Theranos cited a "positive interaction" with the FDA and said it will resubmit 
 Question:And _ had to void two years of its test results.
answer:

Theranos