The passage highlights the fact that the need of the hour is:-

The stranger came early in February, one wintry day, through a biting wind and a driving snow, the last snowfall of the year, over the down, walking from Bramblehurst railway station, carrying a little black portmanteau in his thickly gloved hand. He was wrapped up from head to foot, and the brim of his soft felt hat hid every inch of his face but the shiny tip of his nose; the snow had piled itself against his shoulders and chest, and added a white crest to the burden he carried. He staggered into the 'Coach and Horses' more dead than alive, and flung his portmanteau down. "A fire," he cried, "in the name of human charity! A room and a fire!" He stamped and shook the snow from off himself in the bar, and followed Mrs. Hall into her guest parlour to strike his bargain. And with that much introduction, and a couple of sovereigns flung upon the table, he took up his quarters in the inn.

Mrs. Hall lit the fire and left him there while she went to prepare him a meal with her own hands. A guest to stop at Iping in winter time was an unheard-of piece of luck, let alone a guest who was no "haggler," and she was resolved to show herself worthy of her good fortune.

What 'good fortune' has struck Mrs.Hall?

To have an occupant in her guest house during the off-season.

The correct answer is Option (2) → To have an occupant in her guest house during the off-season.

The passage explains Mrs. Hall's perspective in the final paragraph: "A guest to stop at Iping in winter time was an unheard-of piece of luck..."

The primary good fortune is securing a paying guest during the winter, which is an unusually slow period ("off-season") for the inn. The fact that the guest was "no 'haggler'" is a secondary detail that contributes to her overall happiness, but the main luck is simply having a guest in February.