Cyclical theories of social change gain popularity during periods of extreme social turmoil.

Cyclical theories reveal that for a long time there were periods of social integration and desintegration, and those happened intermittently, which can be seen through the alternation between moments of growth and stagnation, development and regression, association and dissociation and so forth in various sectors of social life. Since a period of extreme social turmoil would have many of these characteristics, it's expected that these theories become more popular in those times as explanations.

explanation:

even though you have attached neither the chart nor the generalizations, i have located them online. the right answer is d, since they are asking you about a generalization. you can only infer from the chart that between 2008 and 2009 the number of employed workers decreased significantly (from over 115 millions to 107 millions approximately), which signals some type of economic crisis.