Answer:
the coordinates of the center of rotation is (4 , 3)
Step-by-step explanation:
*The line which passes through points (4 , 1) and (4 , 5) is vertical because the points have same x coordinates and its length is 5 - 1 = 4
*The line which passes through points (2 , 3) and (6 , 3) is horizontal because the points have same y coordinates and its length is 6 - 2 = 4
*These two lines intersect each other at their mid-point and this mid-point is the center of rotation
*The mid point is 
or