Workers who have employable skills but are either between jobs or have not yet started their first job after completing their training are part of __________.

The correct choice is functional unemployment, which refers to individuals who are temporarily out of work due to transitioning between jobs, re-entering the workforce after training, or seeking their first employment opportunity. This type of unemployment occurs because workers possess the skills necessary to gain employment but are currently not working, often due to personal circumstances or market conditions that are not affecting their skill set.

Functional unemployment emphasizes that the workers are capable of contributing to the economy but are not engaged in a job at the moment, contrasting with other forms of unemployment. For instance, seasonal unemployment involves fluctuations in employment during specific seasons or times of the year, while cyclical unemployment is directly tied to economic downturns when overall demand for jobs decreases. Structural unemployment arises when there's a mismatch between workers' skills and job requirements due to technological changes or shifts in the economy.