What is a noun and what is the difference between noun and non

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.