question: In the figure above, triangle ABC is inscribed in the circle with center O and diameter AC. If AB = AO, what is the degree measure of angle ABO?
  Choices:
  A.15*\degree
  B.30*\degree
  C.45*\degree
  D.60*\degree
  E.90*\degree
query_wo: Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
  Question: In the figure above, triangle ABC is inscribed in the circle with center O and diameter AC. If AB = AO, what is the degree measure of angle ABO?
  Choices:
  A.15*\degree
  B.30*\degree
  C.45*\degree
  D.60*\degree
  E.90*\degree
query_cot: Please first conduct reasoning, and then answer the question and provide the correct option letter, e.g., A, B, C, D, at the end.
  Question: In the figure above, triangle ABC is inscribed in the circle with center O and diameter AC. If AB = AO, what is the degree measure of angle ABO?
  Choices:
  A.15*\degree
  B.30*\degree
  C.45*\degree
  D.60*\degree
  E.90*\degree
question_for_eval: In the figure above, triangle ABC is inscribed in the circle with center O and diameter AC. If AB = AO, what is the degree measure of angle ABO?
  Choices:
  A.15*\degree
  B.30*\degree
  C.45*\degree
  D.60*\degree
  E.90*\degree