Answer:
C. Slow growth in productivity
Explanation:
Within the period of 1970s and 1980s , the countries in western hemisphere experienced an energy crises, which caused by the reduction of oil supply from the middle east nations.
Because of this, many industries that directly use this resources (such as automobiles and pipelines for example) experience many problems in maintaining high level of productivity.
Since these sectors employ large number of American citizens, this lead to the the slow growth of average incomes in the United States during the 1970s and 1980s
