Would appreciate  any after applying the composition ro. 90 ry to rswhat are the coordinates of r' and s'?

I tend to think  this is a 90° clockwise rotation through the origin. For such a rotation, for a point P(x,y) is image P' is P'(y, -x).

So for the point R(-3,-1) ⇒ R'(-1, 3)
                          S(-3, -5) ⇒ S'(-5, 3)

The correct answer is C. R'(-1, 3), S'(-5, 3)