Choice "D" is correct. The business cycle is the rise and fall of economic activity relative to its long-term growth trend. During a contraction or a recession, most industries experience a decline in sales and profits. Similarly, during an expansion, most industries experience an increase in sales and profits. However, health care services are typically not affected by business cycles. People need medical services regardless of whether or not the economy is doing well. Thus, the health care industry is the least affected by the business cycle.
Choice "c" is incorrect. During a downturn in economic activity (recession or contraction), firm investment in new plants and equipment typically drops off substantially. Thus, the demand for commercial construction is typically low during a contraction and high during an expansion. Thus, the commercial construction industry is sensitive to the business cycle.
Choice "b" is incorrect. During a downturn in economic activity (recession or contraction) firm investment in new plants and equipment typically drops off substantially. Thus, the machinery and equipment industry is sensitive to business cycles. Sales grow during an expansion, but they tend to decline during a contraction or recession.
Choice "a" is incorrect. The residential construction industry is sensitive to interest rates, unemployment rates, and consumer wealth. All of these fluctuate with the business cycle. As a result, the residential construction industry is sensitive to the business cycle.