How Many Times Should You Practice the Presentation Prior to Its

How many times should you practice the presentation prior to its actual delivery?

A) Not at all. You will worry about it more if you practice and it goes badly.
B) Once, just to make sure that you can fit it within the time available.
C) Twice. Any more than this and you will become too familiar with the material, and your actual presentation will be stilted.
D) As many times as necessary to ensure that you feel confident and comfortable with the material, and are used to hearing the sound of your own voice.