<span>These lines mean that A. the sun is coming up and the fairies should leave. This person says that "he hears the morning lark," which means that the night is ending and the sun is going to come up very soon. This means that the faries should leave as they shouldn't be seen during the day, as night is their realm. These lines do not provide enough information for these other options to be the correct ones. </span>
By putting it as a matter-of-fact statement (assuming everything else was action packed) there is a massive shift that creates contrast in the piece and leaves a very concise point to shock/leave the reader with.
