Answer:
FCFS - First Come First Serve.
Shortest Processing Time.
Critical Ratio.
Explanation:
FCFS - First Come First Serve is the simplest scheduling algorithm that schedules according to arrival times of processes.
Shortest Processing Time: This actually  goes ahead to process the job with the shortest waiting time ahead of all other jobs waiting in the queue.
Critical Ratio: This is calculated by dividing the time remaining for a job's due date by the total actual time remaining for the job.
