Final answer:
Esther embarrasses herself at her scholarship sponsor's house when she calls her sponsor by the wrong name.
Step-by-step explanation:
The correct answer is C. Calls her sponsor by the wrong name.
In the given context, Esther embarrasses herself at her scholarship sponsor's house by addressing her sponsor by the wrong name. This shows a lack of proper etiquette and attention to detail, which could lead to an uncomfortable situation. The embarrassment could stem from not taking the time to verify the correct name or not remembering it correctly.