What’s the difference between “its” and “it’s”

Which sentence in this excerpt from leo tolstoy’s the death of ivan ilyich suggests that ivan ilyich aspired to be part of the elite in society from a young age? a.ivan ilyich was  le phenix de la famille  as people said.  he was neither as cold and formal as his elder brother nor as wild as the younger, but was a happy mean between them—an intelligent polished, lively and agreeable man.b.  even when he was at the school of law he was just what he remained for the rest of his life:   a capable, cheerful, good-natured, and sociable man, though strict in the fulfillment of what he considered to be his duty:   and he considered his duty to be what was so considered by those in authority.c.neither as a boy nor as a man was he a toady, but from early youth was by nature attracted to people of high station as a fly is drawn to the light, assimilating their ways and views of life and establishing friendly relations with them.d.all the enthusiasms of childhood and youth passed without leaving much trace on him; he succumbed to sensuality, to vanity, and latterly among the highest classes to liberalism, but always within limits which his instinct unfailingly indicated to him as correct.e.at school he had done things which had formerly seemed to him very horrid and made him feel disgusted with himself when he did them;