Final answer:
The correct family member is 'neveu' which means nephew in English.
Step-by-step explanation:
The correct answer is neveu, which means 'nephew' in English. In the sentence 'Le fils de mon frère est mon neveu', it is explained that 'Le fils de mon frère' refers to the son of my brother. Therefore, 'neveu' is the correct option to complete the sentence.
Learn more about French family members