Which of the following terms best applies to a very fast increase in economic output which usually occurs before a peak?

a. recession

b. expansion

c. boom

d. recovery

The term which best applies to a very fast increase in economic output which usually occurs before a peak is called a boom - c.

When we're talking about booms, we're talking about high-upwared projected increases of economic output which are then followed by a peak and later on by a small decrease.