Final answer:
The graph that shows the set of transformations is (a).
Step-by-step explanation:
The graph that shows the set of transformations applied to the parent cosine function, which includes a reflection across the x-axis, a shift of 2 units up, and a vertical compression by a factor of 0.5, is graph (a).
In graph (a), the cosine function is reflected across the x-axis, resulting in the same shape but flipped vertically. Then, the function is shifted 2 units up, so all points on the graph are shifted 2 units higher than the original. Finally, a vertical compression by a factor of 0.5 makes the graph narrower and closer to the x-axis.