To determine which sentence best supports the answer in part A, we would need to see the answer provided in that part. However, based on the sentences you have shared, if the answer in part A relates to the laziness or lack of motivation of the sons, then the best supporting sentence would be:
B: As the years went by it became clear even to their father that the boys were lazy.
This sentence directly addresses the theme of the boys' laziness, aligning well with a potential interpretation of part A. If you can provide the answer from part A, I can confirm if this is indeed the best supporting sentence.