What series of transformations from Triangle ABC to Triangle DEF shows that Triangle ABC is congruent to Triangle DEF? a) A reflection across the y-axis and then a translation of 1 unit right, 2 units up
b) A clockwise rotation of 90 degrees followed by a translation to the right 4 and up 4
c) A reflection across the x-axis followed by a translation of 1 right and 1 down
d) A reflection across the line y=x followed by a rotation of 270 degrees