'Before they ate a snack' is the correct answer, it is the adverbial clause of time. A cannot be correct because that is an independent clause, and adverb clause has to be dependent. B isn't a clause at all.
The recording misses opportunities to use sound effects instead of stage directions: Stage instructions are not important in an audio recording, since the movement of the actors will not be seen. For this, recording should display sound effects in place of the instructions to improve the listener's understanding.
The recording follows the original text instead of reinterpreting it: The recording follows the text to the letter, to let the quality of writing is followed with quality.
