ChatGPT:
It depends on the scheduling algorithm used. Based on the information provided, it is not possible to determine the correct sequence of the process when served by the CPU.

If the scheduling algorithm is based on "Priority Scheduling" the correct sequence would be:
D -> C -> B -> A ( as we have to serve the process with the highest priority first)

If the scheduling algorithm is based on "First Come First Serve" the correct sequence would be:
A -> B -> C -> D ( as we have to serve the process that came first)

If the scheduling algorithm is based on "Shortest Job First" the correct sequence would be:
C -> A -> D -> B ( as we have to serve the process with the least burst time first)