In a coordinate plane, triangle ABC has vertices A (1, 1), B (1, 5), and C (5,1). Triangle ABC is translated 3 units right and 2 units down, resulting in triangle A'B'C'. Which rule best describes the transformation of the triangle?

a-(x, y) → (-3x, 2y)
b-(x, y) → (3x, -2y)
c-(x,y) → (x -3, y +2)
d-(x, y) → (x +3, y - 2)