One factor that might limit the human resources available for certain jobs is a

One factor that might limit the human resources available for certain jobs is an inadequate pay level.

Explanation:

Human resource refers to people involved in workforce of the organization. The people working for the company and the department that is responsible for hiring employees in the organization are referred to as human resources.

Human resources are limited, when the supply of individuals who are able and willing to work reduces.

Human resource department focuses on employee benefits like promotion, paying, training and firing employees.

If the payment for certain job is inadequate, then the human resources for that particular job will be limited or reduced.