Unions contribute to
a. both frictional and structural unemployment.
b. frictional but not structural unemployment.
c. structural but not frictional unemployment.
d. neither frictional nor structural unemployment.

The correct answer is D: neither frictional nor structural unemployment

Explanation:

Structural unemployment is a form of unemployment where, at a given wage, the quantity of labor supplied exceeds the quantity of labor demanded because there is a fundamental mismatch between the number of people who want to work and the number of available jobs. It is generally considered to be one of the “permanent” types of unemployment, where improvement if possible, will only occur in the long run.

Structural unemployment is a longer-lasting form of unemployment caused by fundamental shifts in an economy and exacerbated by extraneous factors such as technology, competition, and government policy. The unemployed workers may lack the skills needed for the jobs, or they may not live in the part of the country or world where the jobs are available. Structural unemployment can last for decades and may need radical change to redress the situation.

There is not a direct link between unions and structural unemployment. The main causes are economy shifts, lack of preparation, competiton (for example, factories moving overseas), government policy,  technology shifts, etc.

Frictional unemployment is the time period between jobs when a worker is searching for or transitioning from one job to another. It can be voluntary based on the circumstances of the unemployed individual. Frictional unemployment exists because both jobs and workers are heterogeneous, and a mismatch can result between the characteristics of supply and demand. Such a mismatch can be related to skills, payment, work-time, location, seasonal industries, attitude, taste, and a multitude of other factors.

There is always at least some frictional unemployment in an economy. Economists accept that some frictional unemployment is okay because both potential workers and employers take some time to find the best employee-position match.

There is no direct contribution that unios made to generate or increase frictional unemployment. It causes are found in the description above.