Which is correct: "his head snapped back like an owl's." or, "his head snapped back like an owls'."

Which sentence from an analytical essay contains a gerund acting as the subject of the sentence? a.) in the novel, jason is organizing a revolt against the perceived enemy. b.) public speaking for wilson is a profession but for glenda it is painful necessity. c.) later in the story ella is accused of creating resentment between allison and william. d.) becomes obvious that kate loves causing discord among her coworkers.