In the five-sided star shown, the letters A, B, C, D, and E are replaced by the numbers 3,5,6,7, and 9 , although not necessarily in this order. The sums of the numbers at the ends of the line segments \overline{A B}, \overline{B C}, \overline{C D}, \overline{D E}, and \overline{E A} form an arithmetic sequence, although not necessarily in this order. What is the middle term of the arithmetic sequence?
Answer Choices
A. 9
B. 10
C. 11
D. 12
E. 13