Definition: 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].
Input: "Trust needs to be rebuilt." That's what German Chancellor Angela Merkel firmly asserted early Friday -- as she had the previous day -- in the wake of reports the U.S. National Security Agency had eavesdropped on her cell phone. This claim and others that she and other world leaders have been spied on had "severely shaken" relationships between Europe and the United States, the German leader said. "Obviously, words will not be sufficient," Merkel said in the wee hours Friday at a summit of European Union leaders. "True change is necessary." Talk of the NSA's reported spying on Germany and other allies dominated Merkel's news conference in Brussels, Belgium. It illustrated the anger over this story in Europe and the challenges facing Washington because of it.U.S. official: "Surveillance capabilities, including with ... foreign partners" under reviewGerman leader: "True change is necessary" on part of the U.S.U.S. isn't monitoring Merkel's communications, White House insistsFrance is angry about claims the NSA intercepted millions of phone calls in France 
 Question:The phone numbers were among 200 handed over to the _ by a U.S. official, the memo states.

U.S. National Security Agency