im struggling for geometry would love an answer for this question

Question

on a coordinate plane, each point on ST is defined by coordinate (x,y). the segment is roatated 90 counterclockwise to create ST. which of the following defines a point ST that corresponds to point an ST

a (-y,x)

b (-x,y)

c (x,-y)

d (y,x)

Answer 1

If the rotation is about the origin, (x, y) → (-y, x).