Although much traditional housing in central beijing has been torn down, some courtyard houses (some turned into shops) remain. where would you find these traditional courtyard houses?

In hutongs (alleys)

Explanation:

Beijing was one of the first cities that tried to organize its urban space, creating a road chess of super blocks aligned with the Forbidden City, the residence and central figure of the empire. Within each superquad, Beijing's traditional urban development was in the form of hutongs, small communities of traditional houses with narrow streets occupying part or all of a superquad.

the answer is b, encourage free trade

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