Final answer:
In the book 'The Time Machine', the event that happened first is A. The Time Traveler hosted a demonstration of a model time machine. Therefore, the correct option is A.
Step-by-step explanation:
In the book 'The Time Machine', the event that happened first is A. The Time Traveler hosted a demonstration of a model time machine. This event occurs early in the story when the Time Traveler invites his friends to witness a demonstration of his invention.