Circles with centers (2,4) and (14,9) have radii 4 and 9 , respectively. The equation of a common external tangent to the circles can be written in the form y=m x+b with m>0. What is b ?
Answer Choices
A. \dfrac{908}{119}
B. \dfrac{909}{119}
C. \dfrac{130}{17}
D. \dfrac{911}{119}
E. \dfrac{912}{119}