Correct Answer:
A. A. For
The correct preposition is "For" because it indicates a duration of time, specifically "for the last three days." "Since" is used for a starting point in time, and "About" is grammatically incorrect in this context.
The correct preposition is "For" because it indicates a duration of time, specifically "for the last three days." "Since" is used for a starting point in time, and "About" is grammatically incorrect in this context.