What is defined as a percentage of total room sales payable for rooms booked under a block for a specific event?

The correct choice refers to a percentage of total room sales that is payable for rooms booked under a block for a specific event, commonly known as a commission. This financial arrangement is standard in the hospitality and event planning industries, where event organizers may negotiate a commission rate with hotels or venues. The commission serves as compensation for the hotel’s or venue's role in managing and providing accommodations to the attendees of the event.

When a block of rooms is reserved for an event, the hotel often agrees to provide a certain percentage of the total sales generated from those booked rooms back to the event organizer, incentivizing them to book a larger number of rooms or return to the venue for future events. This practice benefits both parties: the hotel ensures a guaranteed level of occupancy, while the event planner is rewarded with a financial return for their efforts in bringing business to the venue.

The other options reflect different types of fees or charges that do not specifically relate to a percentage of room sales based on event-specific bookings, making them less applicable in this context.