The coordinates of the object image are;
A {5,5}
B{5,1}
C{2,1}
D{1,5}
The rule for rotation of a point {x,y} through 90 degrees about the orgin, is that the object coordinates {x,y} change to image coordinates { y,-x}. This means the coordinates shift positions and the y coordinate acquires a negative sign. So in this case;
A {5,5}------- A' { 5,-5}
B{5,1}----------B' {1,-5}
C{2,1} ---------C' {1,-2}
D{1,5} ---------D' { 5,-1}
Answer
A.