Where does a period or comma go at the end of a quotation

On one of his many outings through the brobdingnagian countryside, gulliver walks on a small path through a field. during this walk on the small path, how does gulliver get dirty? a. the dwarf throws at gulliver, b. the queen of brobdingnagian steps on gulliver, c. gulliver gets caught in a rainstorm, and d. gulliver falls in cow dung.