Deflation refers to which of the following?

Deflation is best defined as a sustained fall in the price of goods and services within an economy. This phenomenon occurs when the general price levels decrease over time, which can lead to a variety of economic effects, including decreased consumer spending, as people may anticipate further price drops. When prices are falling, consumers may delay purchases, expecting better deals in the future, which can further contribute to economic slowdown. Deflation is often associated with reduced demand and can be symptomatic of broader economic issues, such as recession.

The other options do not accurately capture the essence of deflation. High interest rates, lack of regulation in financial services, and high levels of government borrowing pertain to different economic concepts and do not define what deflation is. Therefore, the definition of deflation as a sustained fall in prices is the most accurate choice.