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

[EX Q]: What has been a public health problem in developed countries in the past?, Context: The M. tuberculosis complex (MTBC) includes four other TB-causing mycobacteria: M. bovis, M. africanum, M. canetti, and M. microti. M. africanum is not widespread, but it is a significant cause of tuberculosis in parts of Africa. M. bovis was once a common cause of tuberculosis, but the introduction of pasteurized milk has almost completely eliminated this as a public health problem in developed countries. M. canetti is rare and seems to be limited to the Horn of Africa, although a few cases have been seen in African emigrants. M. microti is also rare and is seen almost only in immunodeficient people, although its prevalence may be significantly underestimated.
[EX A]: tuberculosis

[EX Q]: Einstein created a way of thinking called a?, Context: It was only the orbit of the planet Mercury that Newton's Law of Gravitation seemed not to fully explain. Some astrophysicists predicted the existence of another planet (Vulcan) that would explain the discrepancies; however, despite some early indications, no such planet could be found. When Albert Einstein formulated his theory of general relativity (GR) he turned his attention to the problem of Mercury's orbit and found that his theory added a correction, which could account for the discrepancy. This was the first time that Newton's Theory of Gravity had been shown to be less correct than an alternative.
[EX A]: theory

[EX Q]: In which year was Xiao Xiu born?, Context: A number of sculptural ensembles of that era, erected at the tombs of royals and other dignitaries, have survived (in various degrees of preservation) in Nanjing's northeastern and eastern suburbs, primarily in Qixia and Jiangning District. Possibly the best preserved of them is the ensemble of the Tomb of Xiao Xiu (475–518), a brother of Emperor Wu of Liang. The period of division ended when the Sui Dynasty reunified China and almost destroyed the entire city, turning it into a small town.
[EX A]:
475