Detailed Instructions: 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].
Problem:(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these was more dramatic than the suggestion that these allies should pay more for US troops or risk having these forces withdrawn.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:Similarly, the allies will need to reaffirm the alignment of their policies vis-à-vis _'s nuclear and missile threats.
Solution:
North Korea