ΔABC underwent a sequence of rigid transformations to give ΔA′B′C′. Which transformations might have taken place? A. a reflection across the y-axis followed by a reflection across the x-axis B. a rotation 90° clockwise about the origin followed by a reflection across the x-axis C. a rotation 270° clockwise about the origin followed by a reflection across the x-axis D. a reflection across the x-axis followed by a reflection across the y-axis