Andrea arena is the owner of 2 places at 1 time, a concierge company. she and her staff of 60 perform everyday services such as walking the dog, picking up cleaning, waiting for the repairman, and going to the post office for people who are too busy to perform these simple acts themselves. she is such a caring person and so well liked that her customers recommend her instead of her business to people who are looking for someone to perform similar services. their inability to see the distinction between arena and her services is an example of which unique characteristic of services?

a. intangibility
b. impressionability
c. incongruity
d. inseparability
e. inflexibility