Task: Question Answering
Input (English): Question: Let A, B, and C be three points on circle O such that AC is a diameter of O. Extend line AC
to a point D such that DB is tangent to O at B, and suppose that \ADB = 20o. Compute
\ACB.

 Option A: 32o

 Option B: 47o

 Option C: 55o

 Option D: 68o

 Option E: 71o
Output (English): Option C