What explanations have been given for the decline in Canadian productivity growth since 1973? (Select all that apply.) A. The appearance of a slowdown was caused by measurement error, including in changes in the quality of capital inputs. B. Higher oil prices caused companies to use less energy, causing them to produce less with the same quantities of capital and labour inputs. C. High productivity growth experienced during the 1950s and 1960s was an anomaly, and the slowdown represented a return to a long-term normal rate of productivity growth. D. Extremely high savings rates led to rapid growth in capital stocks