What type of word is “riveting”? A noun or a verb? How do you know?

Excerpt from 100% - the story of a patriot upton sinclair 10 so peter walked along, with his belt drawn tight, and his restless blue eyes wandering here and there, looking for a place to get a meal. there were jobs to be had, but they were hard jobs, and peter wanted an easy one. there are people in this world who live by their muscles, and others who live by their wits; peter belonged to the latter class; and had missed many a meal rather than descend in the social scale. 11 peter looked into the faces of everyone he passed, searching for a possible opening. some returned his glance, but never for more than a second, for they saw an insignificant looking man, undersized, undernourished, and with one shoulder higher than the other, a weak chin and mouth, crooked teeth, and a brown moustache too feeble to hold itself up at the corners. peters' straw hat had many straws missing, his second-hand brown suit was become third-hand, and his shoes were turning over at the sides. in a city where everybody was "hustling," everybody, as they phrased it, "on the make," why should anyone take a second glance at peter gudge? why should anyone care about the restless soul hidden inside him, or dream that peter was, in his own obscure way, a sort of genius? no one did care; no one did dream. 12 it was about two o'clock of an afternoon in july, and the sun beat down upon the streets of american city. there were crowds upon the streets, and peter noticed that everywhere were flags and bunting. once or twice he heard the strains of distant music, and wondered what was "up." peter had not been reading the newspapers; all his attention bad been taken up by the quarrels of the smithers faction and the lunk faction in the first apostolic church, otherwise known as the holy rollers, and great events that had been happening in the world outside were of no concern to him. peter knew vaguely that on the other side of the world half a dozen mighty nations were locked together in a grip of death; the whole earth was shaken with their struggles, and peter had felt a bit of the trembling now and then. but peter did not know that his own country had anything to do with this european quarrel, and did not know that certain great interests throughout the country had set themselves to rouse the public to action. based on the author's characterization of peter in paragraphs 10, 11, and 12, which word best describes him? a) industrious b) loyal c) patriotic d) poor