What set of transformations is performed on ABCD to form A′B′C′D′? (4 points)

a
A translation 1 unit to the left followed by a 180-degree counterclockwise rotation about the origin

b
A translation 1 unit to the right followed by a 180-degree counterclockwise rotation about the origin

c
A 90-degree counterclockwise rotation about the origin followed by a translation 1 unit to the right

d
A 90-degree counterclockwise rotation about the origin followed by a translation 1 unit to the left