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 Rt△ABC, ∠C = 90.0, AC = 4.0, AB = 5.0, then the value of sinB is ()
  Choices:
  (A) \frac{2}{3}
  (B) \frac{3}{5}
  (C) \frac{3}{4}
  (D) \frac{4}{5}