Triangle A B C has A C=3, B C=4, and A B=5. Point D is on \overline{A B}, and \overline{C D} bisects the right angle. The inscribed circles of \triangle A D C and \triangle B C D have radii r_{a} and r_{b}, respectively. What is r_{a} / r_{b} ?
Answer Choices
A. \dfrac{1}{28}(10-\sqrt{2})
B. \dfrac{3}{56}(10-\sqrt{2})
C. \dfrac{1}{14}(10-\sqrt{2})
D. \dfrac{5}{56}(10-\sqrt{2})
E. \dfrac{3}{28}(10-\sqrt{2})