question: Find x for the equilateral triangle R S T if R S = x + 9, S T = 2 x, and R T = 3 x - 9.
  Choices:
  A:3
  B:6
  C:9
  D:12
query_wo: Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
  Question: Find x for the equilateral triangle R S T if R S = x + 9, S T = 2 x, and R T = 3 x - 9.
  Choices:
  A:3
  B:6
  C:9
  D:12
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: Find x for the equilateral triangle R S T if R S = x + 9, S T = 2 x, and R T = 3 x - 9.
  Choices:
  A:3
  B:6
  C:9
  D:12
question_for_eval: Find x for the equilateral triangle R S T if R S = x + 9, S T = 2 x, and R T = 3 x - 9.
  Choices:
  A:3
  B:6
  C:9
  D:12