Answer: D) pay-for-knowledge
Explanation:
Pay-for-knowledge is known to be a form of pay system in which workers after furthering their education and obtaining special academic accomplishment and skill development are recompensed by employers through compensation. The employees after the training get to do more responsibilities and projects in the company due to the new knowledge acquired. Furthermore, this motivates employees to improve their educational attainment and skills. Thus, the form of compensation is usually a higher pay in income.