Which of the following is NOT a useful technique to reduce the average waiting time during a peak demand period in which the demand rate exceeds capacity? 

a. A city charges cars an extra fee for entering the downtown area during rush hour. 

b. A restaurant cuts ingredients in the morning ahead of the lunch rush. 

c. A package delivery company hires independent contractors to assist in the deliveries during the holiday season. 

d. TSA decreases the coefficient of variation of passenger screening times at the airport. 

e. A cruise line requests passengers to select what items they will select from a menu four hours before dinner is served on the ship.