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: It's 8 p.m. in Chelsea, Massachusetts, just across the Mystic River from Boston. For Lt. Detective David Betz, his day is about to get busy. After about 30 minutes, Betz, head of the Narcotics and Vice Division of the Chelsea Police Department, leaves to meet with a confidential informant who has been assisting with a case. "When we make contact with this person, hopefully they will be able to make a call to any number of their sources, and we'll try to buy some heroin off the street tonight. ... This is basically the meat and potatoes of what we do," Betz says.Chelsea, Massachusetts, is in the middle of a heroin epidemicGov. Deval Patrick declared a public health emergency in MassachusettsInformants help detectives get drugs off the street"You're constantly pushing back the ocean, basically," detective says 
 Question:From 2000 to 2012, the number of unintentional opiate overdoses in _ increased by 90%, he said.

Massachusetts