question: \triangle R S T \cong \triangle A B C. Find x.
  Choices:
  A:8
  B:10
  C:13
  D:21
query_wo: Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
  Question: \triangle R S T \cong \triangle A B C. Find x.
  Choices:
  A:8
  B:10
  C:13
  D:21
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: \triangle R S T \cong \triangle A B C. Find x.
  Choices:
  A:8
  B:10
  C:13
  D:21
question_for_eval: \triangle R S T \cong \triangle A B C. Find x.
  Choices:
  A:8
  B:10
  C:13
  D:21