Final answer:
The line that best shows the relationship between the son and father in the poem 'Those Winter Sundays' is 'Sundays too my father got up early.'
Step-by-step explanation:
The line that best shows the relationship between the son and father in the poem 'Those Winter Sundays' is line A: 'Sundays too my father got up early.' This line indicates the father's consistent dedication and sacrifice for his son, even on Sundays when most people would sleep in. It demonstrates the father's love and the son's recognition and appreciation of his father's efforts.