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: With a towering warship behind him, President Barack Obama announced on Tuesday that the U.S. will hand over two ships to the Philippine Navy to boost its maritime security capabilities, in a bid to show that the U.S. and its allies won't be cowed by China in disputed waters far off its coast. Obama said the pair of ships - one U.S. Coast Guard cutter, one research vessel - were part of a broader American plan to scale up assistance to naval forces in Southeast Asia, where coastal nations feel threatened by China's aggressive moves to assert control over the South China Sea.President Obama arrived in Manila midday Tuesday ahead of APEC summitEconomic meeting is designed to plug trade deal - but is clouded by ISISObama recently said he won't step up military activity after Paris attacksOn trip he praised Filipino navy amid mounting South China Sea dispute 
 Question:China claims the waters as its own after building artificial islands there, while the _ insists they are open waters - and has sent warships there to prove the point.

U.S.