TASK DEFINITION: This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
PROBLEM: Passage: The Bell Telephone Company was created in 1877, and by 1886, more than 150,000 people in the U.S. owned telephones. Bell Company engineers made numerous other improvements to the telephone, which emerged as one of the most successful products ever. In 1879, the Bell company acquired Edison's patents for the carbon microphone from Western Union. This made the telephone practical for longer distances, and it was no longer necessary to shout to be heard at the receiving telephone. Question: What addition let people stop yelling into the telephone?

SOLUTION: carbon microphone

PROBLEM: Passage: In military affairs, the use of infantry with specialised roles increased. Along with the still-dominant heavy cavalry, armies often included mounted and infantry crossbowmen, as well as sappers and engineers. Crossbows, which had been known in Late Antiquity, increased in use partly because of the increase in siege warfare in the 10th and 11th centuries.[AB] The increasing use of crossbows during the 12th and 13th centuries led to the use of closed-face helmets, heavy body armour, as well as horse armour. Gunpowder was known in Europe by the mid-13th century with a recorded use in European warfare by the English against the Scots in 1304, although it was merely used as an explosive and not as a weapon. Cannon were being used for sieges in the 1320s, and hand-held guns were in use by the 1360s. Question: What led to the increased use of armor in the 12th century?

SOLUTION: The increasing use of crossbows

PROBLEM: Passage: According to the U.S. Census Bureau, in 2004, Miami had the third highest incidence of family incomes below the federal poverty line in the United States, making it the third poorest city in the USA, behind only Detroit, Michigan (ranked #1) and El Paso, Texas (ranked #2). Miami is also one of the very few cities where its local government went bankrupt, in 2001. However, since that time, Miami has experienced a revival: in 2008, Miami was ranked as "America's Cleanest City" according to Forbes for its year-round good air quality, vast green spaces, clean drinking water, clean streets and city-wide recycling programs. In a 2009 UBS study of 73 world cities, Miami was ranked as the richest city in the United States (of four U.S. cities included in the survey) and the world's fifth-richest city, in terms of purchasing power. Question: As of 2004, what city was the poorest in the United States?

SOLUTION:
Detroit