Read the following SAT test question and then click on a button to select your answer.

In the figure above, the circle with center A and the circle with center C are tangent at point D. If the circles each have radius 10, and if line l is tangent to the circle with center A at point B, what is the value of x?

(A) 55
(B) 60
(C) 63
(D) 65
(E) It cannot be determined from the information given.

来源:可可英语 http://www.kekenet.com/sat/201510/402430.shtml