please answer C only

With the continuous increase in the number of passengers and the emergence of low-cost companies, the commercial aviation sector has become a highly competitive one. Thus, airlines need to operate as efficiently as possible in order to make a profit. The aircraft turnaround stage is one of the most critical processes that airlines and airports have to face in their daily operations. The turnaround of an aircraft comprises all tasks that need to be completed since it arrives to the assigned gate until it is ready for departure. These activities include: boarding and disembarking passengers, cabin-cleaning and catering, aircraft maintenance and re-fueling, loading and unloading of baggage and cargo, security checks, etc. The Table below describes the tasks and steps involved in the aircraft turnaround for Hala Airways. The focus of the process improvement will be for the 1 - 4 pm shift. Tasks Time (Min) Predecessors A. Position Passenger Bridge 1 B. Deplane Passengers 9 A C. Service Galleys 15 A D. Service Cabin 11 B E. Board Passengers 14 C,D,H F. Remove Passenger Bridge 1 E G. Unload FWD Compartment 5 H. Load FWD Compartment 7 K,L,J 1. Unload AFT Compartment 6 9 I J. Load AFT Compartment K. Fuel Airplane 9 G,M 10 G L. Service Vacuum Toilets M. Service Potable Water N. Start Engines 2 0 F a) In case Hala Airways wanted their gate to be serviced by one crew only during the 1 4 pm shift, how many aircrafts can be processed during that shift? What is the cycle time associated with this arrangement? b) Hala Airways would like to increase the number of flights processed to 6 aircrafts/shift. How many actual crews will be needed to achieve this target and what will be the time needed for every flight? What is the efficiency of this arrangement? c) In order to be able to process even more flights, Hala Airways is ready to increase their staff to 7 crews. Help Hala Airways design a system that will process the maximum number of flights with 7 crews. What is the efficiency of the new system