Which guideline historians place arguments in historical context?

historians should assume that people have always thought the same way throughout time.
historians shouldn’t project modern ideas onto the societies that they are studying.
historians should use older versions of technology to find the sources they need.
historians shouldn’t trace how ideas have changed in different eras.

the great wall of china worked as a defense for the feudal states of the zhou dynasty to the north. during the warring states period more walls were put up to defend the borders of the different kingdoms. it was semi successful because despite the wall, the mongols eventually conquered china also the great wall provided protection to the economic development and cultural progress, safeguarded the trading routes such as the silk road, and secured transmission of information and transportation. @jayxboof

the answer is c.richard m. nixon