Final answer:
A placeholder should be placed in front of each guest to show they have been greeted. This is part of event etiquette, especially during meal preparations, ensuring that everyone feels acknowledged.
Step-by-step explanation:
Place a placeholder in front of each guest to show they have been greeted. This polite gesture is part of proper etiquette during a formal event or gathering. It ensures that every attendee feels acknowledged and can also help with organizing the seating arrangements. In the context provided, when guests are being readied for supper, the placeholders could be name cards or small trinkets at their designated seats. The transformation of the sitting-room into a dining-room and the decoration with cut flowers are part of the preparation for a meal at a social event.