Which of the Following Is True About Buffers Such as HEPES

Multiple Choice

Which of the following is true about buffers such as HEPES, TRIS, MOPS, etc.?

A) The Henderson-Hasselbalch equation applies to them.
B) They consist of simple weak acids and bases.
C) They are less resistant to changes in temperature than are other buffers.
D) We can use them interchangeably because they all have the same pK_a.