Which two things must you clearly understand in order to communicate successfully?

A) your audience and your purpose
B) your proposal and your audience
C) your documentation and measures of excellence
D) your software and your hardware

To communicate successfully, it is crucial to have a clear understanding of both the audience you are addressing and the purpose of your communication. A proposal and documentation are not necessarily required for successful communication, and knowledge of software and hardware may be important for specific types of communication but not universally necessary.