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.

[EX Q]: Passage: In the mid-18th century, Paris became the center of an explosion of philosophic and scientific activity challenging traditional doctrines and dogmas. The philosophic movement was led by Voltaire and Jean-Jacques Rousseau, who argued for a society based upon reason rather than faith and Catholic doctrine, for a new civil order based on natural law, and for science based on experiments and observation. The political philosopher Montesquieu introduced the idea of a separation of powers in a government, a concept which was enthusiastically adopted by the authors of the United States Constitution. While the Philosophes of the French Enlightenment were not revolutionaries, and many were members of the nobility, their ideas played an important part in undermining the legitimacy of the Old Regime and shaping the French Revolution. Question: Which philosopher introduced the idea of a separation of powers in government?
[EX A]: Montesquieu

[EX Q]: Passage: Philadelphia's an annualized unemployment rate was 7.8% in 2014, down from 10.0%the previous year. This is higher than the national average of 6.2%. Similarly, the rate of new jobs added to the city's economy lagged behind the national job growth. In 2014, about 8,800 jobs were added to the city's economy. Sectors with the largest number of jobs added were in education and health services, leisure and hospitality, and professional and business services. Declines were seen in the city's manufacturing and government sectors. Question: Unemployment rate in 2014?
[EX A]: 7.8%

[EX Q]: Passage: Historical aspects of the Expo line route are noteworthy. It uses the right-of-way for the Santa Monica Air Line that provided electric-powered freight and passenger service between Los Angeles and Santa Monica beginning in the 1920s. Service was discontinued in 1953 but diesel-powered freight deliveries to warehouses along the route continued until March 11, 1988. The abandonment of the line spurred concerns within the community and the entire right-of-way was purchased from Southern Pacific by Los Angeles Metropolitan Transportation Authority. The line was built in 1875 as the steam-powered Los Angeles and Independence Railroad to bring mining ore to ships in Santa Monica harbor and as a passenger excursion train to the beach. Question: Who bought the Expo line from Southern Pacific?
[EX A]:
Southern Pacific by Los Angeles Metropolitan Transportation Authority