Students must complete two activities to register for class: registration and payment of fees. Because of individual differences, the processing time (in minutes) for each of these two activities for five students varies, as shown below: a. Construct a Gantt chart to determine the total time required to process all five students. Use the following sequence of students: D, E, B, C, A. b. Can you construct a better sequence to reduce the total time required? c. What problems might be encountered in using this approach to registration in colleges