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.

Passage: Between 2000 and 2004 an average of 478 crimes were reported each day in Mexico City; however, the actual crime rate is thought to be much higher "since most people are reluctant to report crime". Under policies enacted by Mayor Marcelo Ebrard between 2009 and 2011, Mexico City underwent a major security upgrade with violent and petty crime rates both falling significantly despite the rise in violent crime in other parts of the country. Some of the policies enacted included the installation of 11,000 security cameras around the city and a very large expansion of the police force. Mexico City has one of the world's highest police officer-to-resident ratios, with one uniformed officer per 100 citizens. Question: What Mexican mayor tried to crack down on crime immensely? 
Marcelo Ebrard

Passage: After the American Revolutionary War, the number and proportion of free people of color increased markedly in the North and the South as slaves were freed. Most northern states abolished slavery, sometimes, like New York, in programs of gradual emancipation that took more than two decades to be completed. The last slaves in New York were not freed until 1827. In connection with the Second Great Awakening, Quaker and Methodist preachers in the South urged slaveholders to free their slaves. Revolutionary ideals led many men to free their slaves, some by deed and others by will, so that from 1782 to 1810, the percentage of free people of color rose from less than one percent to nearly 10 percent of blacks in the South. Question: Who in the south were urging their churches to free their slaves in the south?
Quaker and Methodist preachers

Passage: As anticipated by Nimitz, the Japanese fleet arrived off Midway on 4 June and was spotted by PBY patrol aircraft. Nagumo executed a first strike against Midway, while Fletcher launched his aircraft, bound for Nagumo's carriers. At 09:20 the first U.S. carrier aircraft arrived, TBD Devastator torpedo bombers from Hornet, but their attacks were poorly coordinated and ineffectual; thanks in part to faulty aerial torpedoes, they failed to score a single hit and all 15 were wiped out by defending Zero fighters. At 09:35, 15 additional TBDs from Enterprise attacked in which 14 were lost, again with no hits. Thus far, Fletcher's attacks had been disorganized and seemingly ineffectual, but they succeeded in drawing Nagumo's defensive fighters down to sea level where they expended much of their fuel and ammunition repulsing the two waves of torpedo bombers. As a result, when U.S. dive bombers arrived at high altitude, the Zeros were poorly positioned to defend. To make matters worse, Nagumo's four carriers had drifted out of formation in their efforts to avoid torpedoes, reducing the concentration of their anti-aircraft fire. Nagumo's indecision had also created confusion aboard his carriers. Alerted to the need of a second strike on Midway, but also wary of the need to deal with the American carriers that he now knew were in the vicinity, Nagumo twice changed the arming orders for his aircraft. As a result, the American dive bombers found the Japanese carriers with their decks cluttered with munitions as the crews worked hastily to properly re-arm their air groups. Question: When did the Japanese fleet arrive off Midway?

4 June