Which of the following factors is not relevant in explaining the persistence of wage differentials?

A) Labor immobility.
B) Compensating differences.
C) Free public education.
D) Noncompeting groups.

Wage Differentials

The variations in wage rates due to factors such as occupation, industry, location, and skills level.

Labor Immobility

A situation where workers find it difficult to move between jobs or geographical locations, often due to skills, qualifications, or other barriers.

Compensating Differences

Wage differentials that compensate employees for the desirability or undesirability of a job due to various factors, such as risk, effort, or location.