Let A=(0,9) and B=(0,12). Points A^{\prime} and B^{\prime} are on the line y=x, and \overline{A A^{\prime}} and \overline{B B^{\prime}} intersect at C=(2,8). What is the length of \overline{A^{\prime} B^{\prime}} ?
Answer Choices
A. 2
B. 2 \sqrt{2}
C. 3
D. 2+\sqrt{2}
E. 3 \sqrt{2}