Which of the following statements regarding the small triangles in the IEEE/ANSI symbols for ...

Which of the following statements regarding the small triangles in the IEEE/ANSI symbols for flip-flops is TRUE?
 
  A) Triangles internal and external to the rectangle indicate active LOW inputs are required.
  B) A triangle within the rectangle means edge-triggered and an external triangle indicates an active LOW input.
  C) Internal triangles require active LOW inputs whereas external triangles indicate Don't Care conditions.
  D) A triangle external to the rectangle means edge-triggered and internal triangles indicate active LOW inputs.