Final answer:
Since the 1950s, the natural unemployment rate in Canada has risen and fallen over time, responding to various economic conditions and shifts. The correct option is d.
Step-by-step explanation:
The question inquires about the trend of the natural unemployment rate in Canada since the 1950s. Over the long term, unemployment rates fluctuate due to a combination of economic changes, technological advancements, population growth, and government policies among other factors.
Specifically, this can be seen in the natural unemployment rate, which adjusts over time as the economy and labor force evolve. Looking at patterns derived from historical data, the natural unemployment rate has generally risen and fallen over different periods, responding to economic booms and recessions.
For instance, after the 2008-2009 Great Recession, unemployment rates soared but were predicted to shrink back to lower levels, which tends to support the pattern of fluctuation rather than a steady increase or decrease.
Therefore, the correct answer to the question, 'Since the 1950s, the natural unemployment rate in Canada has:', would be (d) risen and fallen over time. This is supported by historical trends and the understanding that different economic periods will have varied impacts on employment rates, including the natural unemployment rate.