Schlotzky's Deli uses a modified 'Take a Number' system. When a meal is ordered, the customer receives a coaster$-$sized box that lights up and vibrates when the order is ready. What drawback of the 'Take a Number' system is this method attempting to eliminate?

a$.$ The need for the customer to be vigilant.

b$.$ The impersonal nature of the method.

c$.$ The perceived unfairness of the system.

d$.$ The mental connection that a customer could make between the restaurant and a post office.