FERMAT 1999 Problem 20

If \displaystyle a_1=\frac{1}{1-x},a_2=\frac{1}{1-a_1}, and \displaystyle a_n=\frac{1}{1-a_{n-1}}, for n\ge2,x\ne1 and x\ne0, then a_{107} is

Answer Choices
A. \frac{1}{1-x}
B. x
C. -x
D. \frac{x-1}{x}
E. \frac1x