Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.

[EX Q]: Passage: The historian Frederick W. Mote wrote that the usage of the term 'social classes' for this system was misleading and that the position of people within the four-class system was not an indication of their actual social power and wealth, but just entailed 'degrees of privilege' to which they were entitled institutionally and legally, so a person's standing within the classes was not a guarantee of their standing, since there were rich and well socially standing Chinese while there were less rich Mongol and Semu than there were Mongol and Semu who lived in poverty and were ill treated. Question: What did Mote think the Yuan class system really represented?
[EX A]: degrees of privilege

[EX Q]: Passage: The study also found that there were two previously unknown but related clades (genetic branches) of the Y. pestis genome associated with medieval mass graves. These clades (which are thought to be extinct) were found to be ancestral to modern isolates of the modern Y. pestis strains Y. p. orientalis and Y. p. medievalis, suggesting the plague may have entered Europe in two waves. Surveys of plague pit remains in France and England indicate the first variant entered Europe through the port of Marseille around November 1347 and spread through France over the next two years, eventually reaching England in the spring of 1349, where it spread through the country in three epidemics. Surveys of plague pit remains from the Dutch town of Bergen op Zoom showed the Y. pestis genotype responsible for the pandemic that spread through the Low Countries from 1350 differed from that found in Britain and France, implying Bergen op Zoom (and possibly other parts of the southern Netherlands) was not directly infected from England or France in 1349 and suggesting a second wave of plague, different from those in Britain and France, may have been carried to the Low Countries from Norway, the Hanseatic cities or another site. Question: What strains of y. pestis were found in the mass graves?
[EX A]: Y. p. orientalis and Y. p. medievalis

[EX Q]: Passage: Doctor Who has appeared on stage numerous times. In the early 1970s, Trevor Martin played the role in Doctor Who and the Daleks in the Seven Keys to Doomsday. In the late 1980s, Jon Pertwee and Colin Baker both played the Doctor at different times during the run of a play titled Doctor Who – The Ultimate Adventure. For two performances, while Pertwee was ill, David Banks (better known for playing Cybermen) played the Doctor. Other original plays have been staged as amateur productions, with other actors playing the Doctor, while Terry Nation wrote The Curse of the Daleks, a stage play mounted in the late 1960s, but without the Doctor. Question: What was the name of the play performed in the 1970's?
[EX A]:
Doctor Who and the Daleks in the Seven Keys to Doomsday