C. Extrinsic reward.
In this scenario, the sales manager's primary motivation to remain in the job is the high bonuses she earns. The bonuses are external rewards provided by the organization, which fall under the category of extrinsic rewards. Extrinsic rewards are tangible benefits or incentives that are external to the job itself, such as salary, bonuses, promotions, and recognition. In contrast, intrinsic rewards (option A) refer to the internal satisfaction and enjoyment derived from the work itself. Job enrichment (option B) refers to the process of making a job more satisfying and fulfilling by increasing the level of responsibility, autonomy, and challenge. The hierarchy of needs (option D) is a theory proposed by Abraham Maslow, which suggests that individuals are motivated by a series of needs that range from basic physiological needs to self-actualization. While the sales manager's motivation may align with the need for financial security and esteem (which are part of Maslow's hierarchy), the primary motivation described in the scenario is the external reward of high bonuses.