Answer:
b. creation of new products that are essentially free to consumers.
Explanation:
What caused the Measured productivity growth for the United States to have declined following the Great Recession is that the "creation of new products that are essentially free to consumers."
By creating new products that are essentially free for consumers, there is no generated income to raise the nation's productivity growth. The production of free commodities affects GDP negatively and thereby affects the economic development of a country.
Hence, during the Great Recession period, creating new products that are essentially free to consumers caused the measured productivity for the United States to decline.