question: As shown in the figure, PA and PB are tangent to circle O, the tangent EF of circle O intersects PA and PB at points E and F respectively. 
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, PA and PB are tangent to circle O, the tangent EF of circle O intersects PA and PB at points E and F respectively. 
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, PA and PB are tangent to circle O, the tangent EF of circle O intersects PA and PB at points E and F respectively. 
question_for_eval: As shown in the figure, PA and PB are tangent to circle O, the tangent EF of circle O intersects PA and PB at points E and F respectively. 