Which of the Following Statements Regarding the Small Triangles in the IEEE/ANSI

Which of the following statements regarding the small triangles in the IEEE/ANSI symbols for flip- flops is TRUE?

A) A triangle within the rectangle means edge- triggered and an external triangle indicates an active LOW input.
B) Triangles internal and external to the rectangle indicate active LOW inputs are required.
C) A triangle external to the rectangle means edge- triggered and internal triangles indicate active LOW inputs.
D) Internal triangles require active LOW inputs whereas external triangles indicate "Don't Care" conditions.