C& a fast food has four activities in serving a customer: greet customer, take order, process order, and deliver order. each activity is staffed by one employee (for a total of four employees). the processing time for each activity is given as follows:

activity processing time per customer wage rate ($ per hour)
greet customer 2 seconds 5
take order 30 seconds 5
process order 60 seconds 15
deliver order 5 seconds 8

assume demand is unlimited. if two additional employees are added to the current bottleneck activity, what will be the average labor utilization?

(a) 0.400
(b) 0.475
(c) 0.558
(d) cannot be determined.