Q: In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Sentence1: Tom wanted to play a prank on his roommate. Sentence2: Tom asked his roommate's girlfriend for his computer password. Sentence3: Tom logged on to his roommate's computer. Sentence4: Tom changed the background photo to that of a fat shirtless man. Sentence5: Tom laughed like crazy when his roommate saw that nasty background.
A:
Roommate, Roommate's girlfiriend, Tom