Answer:
C. reflection across the x-axis
Step-by-step explanation:
When a point is reflected across the x-axis, the x-coordinate stays the same while the y-coordinate turns into its opposite (positive to negative, negative to positive).
As we can see in the notation, the x-coordinate stayed the same while the y-coordinate went from positive to negative, which tells us that this notation is a reflection across the x-axis.
