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].

Archaeologists say they have unearthed the oldest human footprints ever found in North America. The impressions were discovered buried at a shoreline at an archaeological dig site on Calvert Island, British Columbia in Canada. Charcoal in the prints has been radiocarbon dated, giving them an age of 13,200 years old. The finding was made by the Hakai Institute and the University of Victoria, both in British Columbia. Archaeologists Dr Daryl Fedje and Dr Duncan McLaren excavated an area below the high tide line, and found dozens of human footprints that had remained intact in clay. An ancient skeleton found nearly 20 years ago in a river in Washington is related to Native Americans, says a DNA study that could help resolve a long-running dispute over its ancestry.Human footprints were found preserved on Calvert Island in CanadaThey were radiocarbon dated to a remarkable 13,200 years oldIf confirmed they would be the oldest human footprints in North AmericaDiscovery also suggests people once migrated down the coast 
 Question:'There's no way to get to _ other than watercraft, and that applies to 13,000 years ago as it does today,' Dr McLaren said.
Calvert Island

Washington (CNN) President Barack Obama has hosted plenty of confrontational foreign leaders at the White House, haggling over military aggression, trade disputes and any other irritant that brings a head of state into the Oval Office. When Obama convened the leaders of the Nordic bloc on Friday, it was not one of those meetings. "This was a very useful and important conversation, although there was probably too much agreement to make for as exciting a multilateral meeting as I sometimes participate in," Obama joked after a 90-minute session with the leaders of Finland, Norway, Sweden, Iceland and Denmark Friday. Amid turmoil in the Middle East, cross-border aggression in Eastern Europe, maritime disputes in Asia and restive governments in South America, the northern European nations remain an oasis of liberal cool for a president who has sometimes been described in similar terms.President Obama will host a state dinner to honor five Nordic nationsObama has praised the countries' stability 
 Question:It's no wonder Obama is fond of musing to his aides, "Why can't all countries be like the _ countries?".
Nordic

(CNN) -- Casey Anthony is responsible for the 2008 death of her 2-year-old daughter Caylee, a report released Thursday by Florida's Department of Children and Families concludes. A month after a jury acquitted Anthony on murder and child neglect charges, the state agency found that Anthony "is the caregiver responsible for the verified maltreatments of death, threatened harm and failure to protect" in her daughter's death. Carrie Hoeppner, a spokeswoman for the Department of Children and Families, said the report was issued this week as a "professional courtesy" after the sheriff's office and prosecutors finished their work on the case.NEW: The report was released as a "professional courtesy," a state spokeswoman saysThe sheriff's office won't take action based on the report, a sheriff's spokesman saysThe girl's mother "is the caregiver responsible" for her death, the report findsA Florida jury acquitted Casey Anthony on murder charges 
 Question:The report does not address, or substitute for, judgments regarding the guilt or innocence of the caregiver -- in this case, _ -- DCF spokeswoman Hoeppner said.

Casey Anthony