Rotation in either direction by 180° transforms (x, y) into (-x, -y). Reflection across the y-axis transforms (x, y) into (-x, y). The pair of these transformations is the same as a reflection across the x-axis: (x, y) ⇒ (x, -y), which is what your figure looks like.
The appropriate choice is the 2nd one:
Counterclockwise rotation about the origin by 180 degrees followed by reflection over the y-axis
