Final answer:
Apologize and offer alternative beverages when you forget to add the sweetener in a new diet formula for a meeting with senior management.
Step-by-step explanation:
When you realize you forgot to add the sweetener in the new diet formula you created and had planned on serving at a meeting with senior management, the best course of action would be to apologize and offer alternative beverages. Blaming someone else or proceeding with the presentation without mentioning the mistake could damage your credibility and professionalism. Canceling the meeting and rescheduling should only be considered as a last resort if there are no suitable alternatives available.