Which of the following explains why the original Phillips curve relation disappeared or, as some economists have remarked, "broke down" in the 1970s? A. individuals assumed that expected inflation would be zero. B. monetary policy became contractionary. C. individuals expected that high inflation in one year became more likely to be followed by high inflation in the next year. D. individuals assumed the expected price level for the current year would be equal to the actual price level from the previous year.