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) Video appears to show children gathered around someone handing out sweets moments before Saturday's suicide vehicle bombing that killed dozens of evacuees from besieged Syrian villages, the UN's human rights agency said Tuesday. The agency didn't give further details about the footage, such as whether it shows the explosion in Rashidin, a suburb of Aleppo in northwestern Syria. But the statement fits with other reports, including one from a witness who said many of those killed or injured in the attack were children who were picking up handout snacks. No one has claimed responsibility for the blast, in which 126 people -- including 68 children -- were killed, according to the Syrian Observatory for Human Rights monitoring group. Dozens of others were injured, according to Syria Civil Defense, the volunteer rescue groups also known as the White Helmets.Explosion hit people who were leaving their towns on SaturdayThe attack killed 126 people, including 68 children, monitoring group says 
 Question:The explosion happened outside a line of parked buses that were evacuating hundreds of people from two regime-held but rebel-besieged villages in northwest _.
Solution:
Syrian