Academic departments at most universities in Malaysia hire students to perform tasks such as consulting and answering phone calls. The need for such services varies during the working hours (8:00AM to 5:00PM). In a student service department, the minimum number of students needed is: (b) (c) 2 between 8:00AM and 10:00AM, 3 between 10:01 AM and 11:00AM, 4 between 11:01AM and 1:00PM, 3 between 1:01PM and 5:00PM.