In the excerpt from "The Open Window," Framton Nuttel's observations about the room lead him to assume that Mrs. Sappleton must either be married or widowed. The mention of an "undefinable something about the room" suggesting masculine habitation indicates that he perceives a certain domestic arrangement that implies a relationship status for Mrs. Sappleton. Therefore, the correct response is:
He assumes Mrs. Sappleton must either be married or widowed.