Original prompt can be seen at link (updated on Nov 1, 2017 7:00 PM). Live link on course webpage can be seen here.
In this program, We assume that all threads run until at least both have completed one cycle.
Period means how often (in seconds) this thread will run. With a period of 3, process A will want to start every 3 seconds.
Execution says how many seconds the thread needs before it will complete. If A has a period of 5 and an execution of 4 that means that there will only be 1 second left every period to run other processes.
For RMS the priority does not change. EDF will change based on how long the process has been running.