Which of the following could explain the relatively high wages earned by certain medical professionals, like nurse practitioners and physicians? (1 point)

The age of our population leads to a relatively high quantity of labor supplied at any given wage.
The training and certification required for these professions lead to a relatively low quantity of labor supplied at any give wage.
The age of our population leads to a relatively low quantity of labor demanded at any given wage.
The training and certifications required for these professions lead to a relatively high quantity of labor supplied at any given wage.

The training and certification required for these professions lead to a relatively low quantity of labor supplied at any given wage.