Using sentinel-controlled loop, write the code fragment that execute the following tasks: a. Read the student id and mark of Mathematic test several times until the user has entered the student id 9999 to stop the process. b. Count and display the number of students who passed the test (passing mark is 50 and above). c. Count and display the number of students who failed the test (49 and below is failed). d. Count and display the average of student mark.