Option 1 -> The guest not haggling was mentioned as an added bonus, not the primary good fortune.
Option 2 -> The passage explicitly states "A guest to stop at Iping in winter time was an unheard-of piece of luck," indicating guests were rare during winter (off-season).
Option 3 -> Preparing the meal herself was simply her response to the guest's arrival, not the fortune itself.
Option 4 -> The bargain was struck quickly, but this wasn't highlighted as the source of her good fortune.
Hence, Option 2 -> The passage clearly emphasizes that having ANY guest during winter was "an unheard-of piece of luck" for Mrs. Hall's inn, as Iping typically had no visitors in the off-season. The fact that he also didn't haggle was mentioned as an additional benefit ("let alone a guest who was no 'haggler'"), making this unexpected winter occupancy even more fortunate -> correct