Answer:
Its angle measures.
Explanation:
Notice that the transformations are a rotation and a dilation.
Rotations are rigid transformations, which only changes their position, but dilation changes their size.
That means, the final figure doens't have the same size or position as the original. The only things that remain the same are the angles, beacuse the final figure is similar to the initial, which means their angles are congruent.
Therefore, the right answer is the third choice.