A macroeconomist is presented with a 50-year economic history of two neighboring countries, Country A and Country B. Both countries started with similar population sizes, natural resources, and levels of industrialization. However, their economic paths diverged significantly:

• Country A: Experienced stable inflation, consistently averaging between 2-4% annually.
• Country B: Suffered from extreme economic volatility, with inflation rates swinging wildly from 5% to over 500% in some years, including several periods of hyperinflation followed by sharp recessions.

Based on this stark contrast, what is the primary, overarching question that a macroeconomist would investigate to understand the root cause of these different outcomes?