question: Hint: Please answer the question and provide the correct option letter, e.g., A, B, C, D, at the end.
  Question: As shown in the figure, in the diamond ABCD, two diagonal lines AC = 12.0, BD = 16.0, then the edge length of this diamond is ()
  Choices:
  (A) 10
  (B) 8
  (C) 6
  (D) 5