Answer:
The hotel is experiencing an A) Expectations gap
Step-by-step explanation:
An Expectations gap is a gap between what the customer reasonably expects according to the characteristics of the service, the market information, and the general standards (in this case the hotel), and what the service actually provided.
In the question, Mary's expectations on the hotel were reasonable: she expected her room to be ready, as anyone who booked a room at a hotel would, she expected breakfast to be fresh, a singer who sang in tune, etc.
These are not unfeasible expectations, but the hotel was not able to meet them anyway. The hotel is having a serious expectations gap.