In this task, you are given a question and a context passage. You have to answer the question based on the given passage.

Q: What was formed in 1850 to help with policing?, Context: In the American Old West, policing was often of very poor quality.[citation needed] The Army often provided some policing alongside poorly resourced sheriffs and temporarily organized posses.[citation needed] Public organizations were supplemented by private contractors, notably the Pinkerton National Detective Agency, which was hired by individuals, businessmen, local governments and the federal government. At its height, the Pinkerton Agency's numbers exceeded those of the United States Army.[citation needed]

A: Pinkerton National Detective Agency
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Q: How can you reduce the jnd?, Context: The just-noticeable difference (jnd) (the threshold at which a change is perceived) depends on the tone's frequency content. Below 500 Hz, the jnd is about 3 Hz for sine waves, and 1 Hz for complex tones; above 1000 Hz, the jnd for sine waves is about 0.6% (about 10 cents). The jnd is typically tested by playing two tones in quick succession with the listener asked if there was a difference in their pitches. The jnd becomes smaller if the two tones are played simultaneously as the listener is then able to discern beat frequencies. The total number of perceptible pitch steps in the range of human hearing is about 1,400; the total number of notes in the equal-tempered scale, from 16 to 16,000 Hz, is 120.

A: two tones are played simultaneously
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Q: What might be expressed in a political advertisement on television?, Context: To distinguish official campaigning from independent campaigning, political advertisements on television were required to include a verbal disclaimer identifying the organization responsible for the advertisement. Advertisements produced by political campaigns usually included the statement, "I'm [candidate's name], and I approve this message." Advertisements produced by independent organizations usually included the statement, "[Organization name] is responsible for the content of this advertisement", and from September 3 (60 days before the general election), such organizations' ads were prohibited from mentioning any candidate by name. Previously, television advertisements only required a written "paid for by" disclaimer on the screen.

A:
"I'm [candidate's name], and I approve this message."
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