The two circles pictured have the same center C. Chord \overline{A D} is tangent to the inner circle at B, A C is 10 , and chord \overline{A D} has length 16 . What is the area between the two circles?
Answer Choices
A. 36 \pi
B. 49 \pi
C. 64 \pi
D. 81 \pi
E. 100 \pi