question: As shown in the figure, triangle ODC is the figure obtained by rotating triangle OAB clockwise around point O by 30.0. If point D happens to fall on AB, and the degree of angle AOC is 100.0, then the degree of angle DOB is ()
  Choices:
  A:40°
  B:30°
  C:38°
  D:15°
query_wo: Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
  Question: As shown in the figure, triangle ODC is the figure obtained by rotating triangle OAB clockwise around point O by 30.0. If point D happens to fall on AB, and the degree of angle AOC is 100.0, then the degree of angle DOB is ()
  Choices:
  A:40°
  B:30°
  C:38°
  D:15°
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: As shown in the figure, triangle ODC is the figure obtained by rotating triangle OAB clockwise around point O by 30.0. If point D happens to fall on AB, and the degree of angle AOC is 100.0, then the degree of angle DOB is ()
  Choices:
  A:40°
  B:30°
  C:38°
  D:15°
question_for_eval: As shown in the figure, triangle ODC is the figure obtained by rotating triangle OAB clockwise around point O by 30.0. If point D happens to fall on AB, and the degree of angle AOC is 100.0, then the degree of angle DOB is ()
  Choices:
  A:40°
  B:30°
  C:38°
  D:15°