问题：

[单选] Which agent will be selected when the Resource Selection Criteria is set to circular routing?（）

A . the agent who has been in the Available state for the longest amount of time  
B . the next available agent with the highest priority, as determined by the agent order in the Resources list
C . the next available agent, based on the last agent selected and the agent order in the Resources list  
D . the agent assigned to the selected Resource Group and is thus qualified to be selected