Final answer:
In 'The Metamorphosis', Gregor's father throws an apple at Gregor, which lodges in his back and injures him. This signifies Gregor's increasing alienation from his family (option 3).
Step-by-step explanation:
The question refers to an incident from novella 'The Metamorphosis', in which the character Gregor's father throws an object at him. In the story, during a fit of anger, Gregor's father throws an apple at Gregor, which ends up lodging in his back, significantly injuring him. This violent act signifies the increasing alienation and dehumanization of Gregor in the eyes of his family, as he transforms into a grotesque insect-like creature. The apple, stuck in Gregor's back, is a stark symbol of the pain and isolation he feels as his family's patience and sympathy for him start to wane.
Hence, the answer is option 3.