If You Have Agreed to Speak to an Audience with Which

If you have agreed to speak to an audience with which you are unfamiliar,what is the best thing to do?

A) Take your best guess as to who will be in your audience.
B) Contact each audience member individually to try to get to know him or her before your presentation.
C) Ask for the names of a half dozen people who will be in the audience and contact them.
D) Plan the presentation based on what interests you the most.