You will be given a definition of a task first, then some input of the task.
In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.

Passage: In the 1960s, in an undetermined place in the Alps, an eagle couple has two hatching eggs. When both eaglets are born, their mother knows that she must only raise one as their successor. In an ensuing fight with another eagle, the eaglets' father dies when he crashes to the ground. One of the eaglets shortly falls from the nest, and his mother, due by nature to maintain the survivor, ignores the eaglet's cry for help.
In the meantime, forester Danzer meets with a boy named Lukas and his father Keller. They both live in a new house in the mountains, after the death of Maria, mother of Lukas and Keller's wife, as a result of a fire. Keller, gravely afflicted by the death of his wife, fails to live in harmony and understanding with his son, who takes refuge more and more in nature, avoiding contact with his father. As a retreat Lukas constantly goes to the remains of his old house, where he often sees the photograph of his deceased mother.
As Lukas' dog Scout is taking a walk in the forrest, Lukas comes across the eaglet, and Lukas decides to raise him to full health. Lukas takes the eaglet to his old house to take care of him. Danzer also meets the eaglet, and decides to help Lukas for the affection he feels for him.
The forester tells Lukas that the food he has given the eaglet is not good. He also tells him to give sunlight to the eaglet. When a fox sneaks in and kills Keller's hens, he angrily chases Lukas. Lukas, fearful for the safety of the eaglet, goes to his family's hut. Lukas rescues the eaglet from the attacking foxes. As Lukas stays and reads his family's Bible, he comes across the story of Cain and Abel. Aptly fitting the eaglet's own story, Lukas names it Abel.
Output:
Who was married to the father of the boy that the forester meets?