Instructors providing evidence that student efforts make a difference is an example of:

When instructors provide evidence that student efforts lead to meaningful outcomes, they are effectively motivating and encouraging students. This approach helps students understand the connection between their hard work and the results they achieve, reinforcing their belief in the value of their efforts. By highlighting success stories or demonstrating how a student's performance improves as a direct result of their engagement, instructors foster a supportive learning environment. This motivation is essential for encouraging students to put forth their best effort and persist even when faced with challenges.

Other options, while relevant in different contexts, do not address the specific dynamic of reinforcing student effort through validation and encouragement as effectively as motivating and encouraging students does.