Motivation can originate from internal or external sources. According toHuman Resource Management, 16th Editionby Gary Dessler,intrinsic motivationoccurs when employees are driven by internal satisfaction, enjoyment, or fulfillment derived from the work itself rather than external rewards.

Employees who find their work meaningful, challenging, or personally rewarding are intrinsically motivated. Dessler emphasizes that intrinsic motivation is associated with higher levels of engagement, creativity, and long-term commitment because the motivation comes from within the individual rather than from pay, bonuses, or promotions.

External, extrinsic, or incentive motivation refers to behavior driven by external rewards or avoidance of punishment. Since the question specifies fulfillment from the work itself, the correct classification isintrinsic motivation.

Source:

Gary Dessler,Human Resource Management, 16th Edition, Chapter on Employee Motivation and Engagement