Answer:
D
Explanation:
Letter D is the only answer that gets the transformation of triangle ABC correct, since it is the only answer that describes a reflection across line p.
Letter A describes a reflection across the y-axis, which is incorrect because the triangle on the right is farther away from the y-axis than the triangle on the left.
Letter B describes a reflection across the x-axis, which is incorrect because the topmost triangle is farther away from the x-axis than the bottommost triangle.
Letter C once again describes a reflection across the y-axis, which is incorrect for the same reason as to why letter A is incorrect.
Therefore, the answer must be letter D.