Questions: The level of output that the economy would produce if all prices, including nominal wages, were fully flexible is called: real GDP. Keynesian output. structural output. potential output.

The answer is the fourth one: potential output.

Explanation for each option:

1. Real GDP: This refers to the total value of all goods and services produced in an economy, adjusted for inflation. It measures the actual output of an economy at a given time, not necessarily when all prices and wages are flexible.

2. Keynesian output: This term is not standard in economic terminology. Keynesian economics focuses on total spending in the economy and its effects on output and inflation, but it does not specifically refer to the output level when all prices and wages are flexible.

3. Structural output: This term is not commonly used in economics to describe the output level when prices and wages are flexible. It might refer to output determined by the structural characteristics of an economy, but it is not the correct term in this context.

4. Potential output: This is the correct term. Potential output is the level of output that an economy can produce when operating at full capacity, with all prices and wages fully flexible. It represents the maximum sustainable output level without causing inflation.

In summary, the level of output that the economy would produce if all prices, including nominal wages, were fully flexible is called potential output.