What concept reflects the sense that individual actions can "make a difference" in achieving important goals?

The correct choice reflects the understanding that when individuals perceive their actions as significant in contributing towards achieving important objectives, it instills a sense of purpose and motivation. This concept embodies the belief that one's contributions and efforts have tangible outcomes, affecting both personal and collective goals.

While other terms like autonomy, self-efficacy, and meaningfulness relate to aspects of personal agency and motivation, they do not specifically encapsulate the idea of making a difference in the same way that "impact" does. Autonomy speaks to the freedom and independence of choice; self-efficacy focuses on one's belief in their ability to accomplish tasks; and meaningfulness involves the significance one places on their work or responsibilities. However, none of these explicitly convey the notion of individual actions leading to noticeable effects on goals, which is the essence of impact.