Final answer:
The correct answer to the fill-in-the-blank question is 'waive.' The term 'waive' means to voluntarily give up a right or claim, fitting the context of the sentence where the sons give up their claims to their father's estate.
Step-by-step explanation:
The correct answer to the question is 'c) waive'. In the given sentence, the most appropriate term for the sons giving up their claims to their father's estate in favor of their mother is 'waive'. The word waive means to refrain from insisting on or using a right or claim. Therefore, the sentence reads: 'Both sons agreed to waive their claims to their father's estate in favor of their widowed mother.'
This choice is supported by a historical understanding from ancient legal codes asserting family and property rights. For example, an edict states that if after the death of her husband the sons raise no claim, the mother can bequeath her property to the son of her choosing, implying that the sons would need to waive any legal claims they might have to allow this to occur.