A circle has center (-10,-4) and radius 13. Another circle has center (3,9) and radius \sqrt{65}. The line passing through the two points of intersection of the two circles has equation x+y=c. What is c ?
Answer Choices
A. 3
B. 3 \sqrt{3}
C. 4 \sqrt{2}
D. 6
E. \dfrac{13}{2}