Jack graduated from law school and took his mom to dinner after the ceremony. At the restaurant, the server filled their water glasses, checked on their table, and took care of their requests. Jack noted that the last time he was at this restaurant, the experience was much worse. This scenario illustrates the ______ of services.
a) inconsistency
b) uniqueness of the service
c) impressionability
d) intangibility
e) inseparability