Triangle RST has vertices R(6, 5), S(9, −4), and T(10, 1). Triangle RST has vertices R′(6, −5), S′(9, 4), and T′(10, −1).

Which transformation of triangle RST produced triangle RST?


a rotation of 90° clockwise around the origin

a rotation of 90° counterclockwise around the origin

a reflection across the y-axis

a reflection across the x-axis