Bram Stoker' s 1897 novel Dracula portrayed vampires -- the "undead" who roam at night to suck the blood of living people -- as able to turn into bats. As a result of the pervasive influence of this novel, many people now assume that a vampire' s being able to turn into a bat is an essential part of vampire myths. However, this assumption is false, for vampire myths existed in Europe long before Stoker' s book. Which one of the following is an assumption on which the argument depends? ['Vampire myths in Central and South America, where real vampire bats are found, portray vampires as able to turn into bats.', 'At the time he wrote Dracula, Stoker was familiar with earlier European vampire myths.', "At least one of the European vampire myths that predated Stoker's book did not portray vampires as strictly nocturnal.", "At least one of the European vampire myths that predated Stoker's book did not portray vampires as able to turn into bats."]