Answer:
The answer is letter A) The unexpected blackout occurred near the masquerade ball.
Step-by-step explanation:
In all the sentences provided, we have similar information. We know an unexpected blackout occurred, and we know it has some connection to a masquerade ball. But in options A, C, and D, the prepositions "before", "during", and "after" tell us when the blackout happened. That means they concern time, not place. However, in letter A, the preposition "near" establishes a clear place connection between the blackout and the ball. We now know an approximate location. We know the blackout occurred near the ball, in a place that is not distance from the ball. This is, therefore, the best option to answer the question.
Near is a preposition that indicates a short distance between things, people, places etc.