Which of the following is considered a non-monetary factor influencing labor supply?

Promotion opportunities are regarded as a non-monetary factor influencing labor supply because they relate to potential career advancement and personal development rather than direct financial compensation. Employees often value opportunities for advancement as they can lead to enhanced job satisfaction, recognition, and long-term benefits, which may not translate immediately into monetary rewards. Such non-monetary incentives can heavily influence an individual's decision to remain with or join a particular organization, as they reflect the potential for growth and fulfillment beyond the immediate pay scale.

In contrast, the other options focus primarily on monetary compensation or benefits directly tied to an employee's financial remuneration. Salary bonuses and overtime pay provide immediate financial benefits, while health insurance, although valuable, is typically classified as a monetary incentive since it is a tangible financial benefit provided as part of employment compensation packages.