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].

Washington (CNN) -- President Barack Obama used a Memorial Day ceremony to say it is time for America to properly welcome home Vietnam veterans and show them and their families the respect and gratitude they deserved but didn't receive decades ago. "You came home and sometimes were denigrated when you should have been celebrated," Obama said beneath a scorching sun at the Vietnam Veterans Memorial. "It was a national shame, a disgrace that should have never happened. That's why here today, we resolve that it will not happen again." The event, which launched a 13-year Vietnam War 50th anniversary commemoration, was the culmination of a day of somber events on the annual holiday honoring America's war dead.NEW: President Obama calls the denigration of Vietnam veterans a "national shame""America will be there for you," Obama tells veterans and their familiesMemorial Day launches a 13-year commemoration of the Vietnam War's 50th anniversaryObama lays a wreath to the fallen at Arlington National Cemetery 
 Question:This year marks the 50th anniversary of the _ deploying a significant military presence in Vietnam.
America

Shocking police dashcam footage has emerged showing an Arizona cop speeding down a road, mounting a sidewalk and smashing into an alleged armed robber in a supposed bid to capture him. In the two videos, Mario Valencia is captured walking along a street in Marana, northwest of Tucson, carrying what appears to be a rifle. He points the loaded weapon into the air and a shot rings out. A police officer in one of the patrol cars says: 'One round just went out. He's definitely loaded.' He then tells his colleague, Officer Michael Rapiejko, in the other vehicle: 'Stand off, the gun is loaded.'Footage shows Mario Valencia walking along a street in Marana, ArizonaAlleged robber points item that appears to be rifle into air; shot rings outSeconds later, Officer Michael Rapiejko starts speeding toward ValenciaHis police car mounts the sidewalk, before crashing into armed suspectValencia taken to hospital with serious injuries; released two days laterPolice chief has defended officer's actions, which saved 'Valencia's life'Suspect had allegedly stolen rifle from Walmart and threatened suicideComes as US police remain under scrutiny for alleged racially profiling 
 Question:_ was put on standard administrative leave after the crash, because it was considered use of force.
Michael Rapiejko

(CNN) Temporary barriers appeared to prevent serious flooding Tuesday in Iowa's second-largest city, but officials are warning thousands of evacuated Cedar Rapids residents to stay away for a couple more days. "It's not time yet to go back to life as usual, but we're getting close," City Manager Jeff Pomeranz told reporters late Tuesday morning after the Cedar River crested there just above 22 feet -- 6 feet above what is considered major flood stage. "It's not over yet, but we're feeling very good ... that this temporary system that we built" will protect the city of more than 120,000 people, Pomeranz said.More than 10,000 residents have evacuatedIowa's National Guard has deployed more than 400 soldiers 
 Question:_ city workers, contractors, volunteers and National Guard troops had hastily erected a system of temporary walls, levees and 250,000 sandbags around the city over the weekend -- and it appeared to be holding, officials said Tuesday.

Cedar Rapids