B is the answer
just like the picture
( T' is not exact. it just shows the reflection)
12÷3=4
cause 1/3 in this situation is 3 cause 12÷4 is 3
(8, 9) will be the midpoint of the segment.
You can find this by applying the formula
(x1 + x2)/2 , (y1 + y2)/2