If I understand the problem correctly, they want you to find the bisector (midpoint) of the line connecting the two points. To do this, you simply find the difference between each of the component parts and divide by 2. For x, 9-1 = 8, divided by 2 gives you 4. So, the midpoint in terms of x is 4 units to the right of x = 1. Do the same for y and you should get the midpoint to be (5, 3). Plug these (x,y) values into the answers, the only one that holds true is A. Hope this helped.
