In a multiple-priority queuing model, arriving customers are assigned to different priority classes based on predetermined criteria, and customers within each class are served on a first-come, first-served basis. What is the purpose of assigning customers to different priority classes in this model?
1) To ensure that high-priority customers are served before low-priority customers
2) To randomly distribute customers across different priority classes
3) To delay the service of high-priority customers
4) To serve customers based on their arrival time