When we speak about family relations, especially when we start the sentence with the name of that relation, an article is not used. The given sentence is correct and does not need to be changed. Hence Option A is correct. Option B is incorrect because we begin the sentence with the noun who is a family member, 'the' is used in exceptional cases when the noun is in the middle of the sentence or when it is followed by an identifying clause. Option C is incorrect because even though the noun begins with a vowel, it is not a non-specific noun. Similarly, option D is incorrect because the noun is not non-specific (It's not just any uncle, it is the uncle who treated us to an ice cream).