Answer:
d. the family sees a light ahead
Explanation:
The text shows that a family that was living in a situation of misery, they were hungry, exhausted and dirty. They needed some support to make their situation change and have a better life. In the text, the characters start to feel hopeful when they see a light that represents Aunt Nancy's house is close, they know that when they get to her house, their luck would change and they would have a more comfortable life. For this reason, we can conclude that the detail of selection that symbolizes a change in family fortune is when the family sees a light ahead.