AMC 10B 2008 Problem 11

Suppose that \left(u_{n}\right) is a sequence of real numbers satisfying u_{n+2}=2 u_{n+1}+u_{n}, and that u_{3}=9 and u_{6}=128. What is u_{5} ?

Answer Choices
A. 40
B. 53
C. 68
D. 88
E. 104