Carrie

Shy, bullied high school student Carrie White (Sissy Spacek) experiences her first period as she showers with other girls after gym class. Unsure of what is happening to her, she panics and pleads for help. The other girls respond by pelting her with hygiene products, laughing and chanting "plug it up!" Gym teacher Miss Collins (Betty Buckley) breaks up the commotion and attempts to console Carrie, a light bulb mysteriously breaking as Carrie reaches the height of her panic.
Later, the school principal seems uncomfortable as Miss Collins expresses bewilderment that Carrie is so uninformed. As he dismisses Carrie from school, she becomes frustrated that he repeatedly calls her by another name, causing an ashtray to fall from his desk and shatter. On her way home, a young boy teases Carrie, and she makes him fall off his bicycle with just a look. At home Carrie is abused by her fanatically religious mother, Margaret (Piper Laurie), who rants about menstruation being the result of sinful thoughts. Carrie is locked in a small closet and ordered to pray for forgiveness. When she is finally allowed to return to her room, Carrie gazes into her reflection, causing the mirror to shatter.
Carrieâs classmate Sue (Amy Irving) feels guilty, so she arranges for her boyfriend, handsome and popular Tommy (William Katt), to ask Carrie to the prom. Reluctant at first, Carrie accepts after encouragement from Miss Collins. Another classmate, Chris (Nancy Allen), skips her detention for bullying Carrie, so she is banned from the prom. Swearing vengeance, she recruits her delinquent boyfriend Billy (John Travolta) to play a prank on Carrie. They slaughter pigs from a nearby farm and place a bucket of their blood above the stage at the schoolâs gymnasium.
Margaret discovers Carrie's prom plans and attempts to abuse her again. Having researched her telekinesis, Carrie asserts her power and stands up to her mother. Margaret responds by accusing Carrie of being a satanic witch.
At the prom, Carrie finds acceptance among her peers and shares a kiss with Tommy. Chris' bubbly best friend Norma (P.J. Soles) rigs the election and Carrie is crowned Prom Queen. Carrieâs joy is cut short when Chris pulls a rope to dump the pigs' blood on her. Chris and Billy escape through a back door, while the bucket falls on Tommy's head, knocking him unconscious. The blood-soaked Carrie hallucinates that everyone in the gymnasium is laughing at her and soon unleashes telekinetic fury upon the crowd, guilty and innocent alike. The doors slam shut (crushing a pair of students), a high-pressure water hose assaults many people (including Norma, who is knocked unconscious), the principal is electrocuted, and Miss Collins is crushed to death. As the gym catches fire, Carrie calmly walks out and locks the remaining students inside. Chris and Billy attempt to run over Carrie as she walks home, but Carrie causes their car to flip and explode.
At home Carrie is comforted by her mother, who reveals her guilt about giving birth to Carrie, a product of marital rape. As they pray together, Margaret stabs her daughter in the back and pursues her through the house. Defending herself, Carrie causes kitchen utensils to fly through the air and crucify Margaret. Distraught over her mother's death, Carrie loses control of her powers as the house crumbles and burns down around her.
Sometime after Carrieâs death, Sue, the sole survivor of the prom massacre, dreams of laying flowers on the charred remains of Carrie's home. As a bloody arm reaches from the rubble and grabs her, Sue wakes up screaming.

Question: Where does Margaret stab her daughter?
Answer: back