Given the task definition and input, reply with output. In this task, you will be shown an extract from a movie plot and a question. You need to provide the correct answer for it. Short answers containing words that are present in the passage are preferred.

The film opens with an old man and another man sitting on a bed in an apartment building. The old man talks about why he was in prison (he slept with his daughter).The camera then pans out the window to a gay club called "The Rectum". The police have arrived and they are wheeling out a body that has obviously been assaulted. People seem to be yelling and swearing to the person on the stretcher.Then, a flashback occurs to two men frantically searching in "The Rectum" for a man whose name is "La Tenia". It is unclear at this point who La Tenia is. One of the men is the person who was being carried out of the club before. He asks around to people in the club, but nobody will answer. Instead, the people ask him to perform sexual acts on them. Eventually, the man searching for La Tenia finds a man whom he thinks is La Tenia and the other man smashes his face in with a fire extinguisher, killing him.The film flashes back again to a street. Prostitutes are standing on corners. The two men who were in the club, whose names are revealed to be Pierre and Marcus, are asking to find a man named Guillermo Nunez. They are referred to a prostitute named Concha, who is actually a male transvestite, who knows where La Tenia is. He refuses to tell and they beat him. He does reveal that he is in The Rectum.The film flashes back to Pierre and Marcus leaving a party. The walk outside and the police are wheeling a body out of a tunnel. Marcus identifies the woman as his girlfriend, Alex. She has been brutally beaten and is unconscious. A man approaches Marcus and asks him if he wants revenge. Marcus replies yes.The film flashes back again to the party. Alex, Marcus, and Pierre socialize with friends. Marcus is drunk and under the influence of drugs. After Marcus acts inappropriately, Alex leaves. She tries to get a taxi, but is unable to. A prostitute recommends to take the underground walkways because they are safer. After she enters it, she sees La Tenia threatening prostitute Concha with a knife. As he sees Alex, he lets her go and grabs Alex, afterwards raping and beating her brutally for nine minutes. During the act a person appears in the background and disappears.Further back in time, Alex, Pierre, and Marcus walk in the subway to get to the party. It is revealed that Pierre was originally Alex's boyfriend, but Marcus is her new boyfriend. Pierre does not seem to have any problem with that.Flashing back to a couple hours before, Marcus and Alex are lying in their bed just after they woke up. Pierre calls and lets them know that his car has broke down and they have to take the subway instead. After Marcus leaves to buy some liquor, Alex finds out that she is pregnant with Marcus' child.In the final scene, Alex sits in a park reading a book while children play. She is completely unaware of her uneventful fate. The scene fades into flashing strobe lights and shows a final slide saying LE TEMPS DETRUIT TOUT (time destroys all things)., Question: Who is the father of Alex's child?
Answer: Marcus