Question:

_______, after a few hours, we were able to open the doors and get out of the elevator.
Which of the following words is most appropriate to complete the sentence above?

A Finally

Explaination

Finally is defined as “at last,” “in conclusion” or “at the end.” It makes the most sense in this sentence as it comes before the context clue “after a few hours” and also sounds appropriate in the context that the speaker is exasperated after having spent hours locked in an elevator.
In spite of means “even though” and would not fit appropriately in this sentence.
As an example would be used to elaborate on an initial statement.
Before contradicts the key phrase that follows: “after a few hours.”