(25 POINTS) Parallelogram ABCD is rotated 90° counterclockwise. What rule shows the input and output of the rotation, and what is the new coordinate of A′ ? A = (-5, 1)

a. (x, y) → (−x, −y); A′ is at (5, −1)
b. (x, y) → (−y, x); A′ is at (−1, −5)
c. (x, y) → (y, −x); A′ is at (1, 5)
d. (x, y) → (x, −y); A′ is at (−5, −1)