Final answer:
After analyzing the provided x and y values, the rule that describes this function is y = -3x, corresponding to option B.
Step-by-step explanation:
The student is looking to find the rule that best describes the given function based on the pairs of x and y values. By examining the ordered pairs (-39, -13), (0, 0), and (3, -9), we can determine the relationship between x and y. We observe that when x increases by 3 (from -39 to -36, and then from 0 to 3), y decreases by 9 (from -13 to -22, and then from 0 to -9). This pattern suggests that for every single unit increase in x, y decreases by 3. Therefore, the rule describing this function is y = -3x, which matches option B.