The correct option is C c
Let’s examine the sentence: “I haven't been to New York before and neither my sister.” The sentence has two clauses joined by the conjunction ‘and.’ The two clauses should follow the same structure as they talk about the same fact. So, the second clause should have equivalents of ‘have’ and ‘not’ from the first clause. The correct equivalent for ‘not’ would be ‘neither’ and ‘have’ would ‘has’ as the object is singular, i.e., ‘sister.’ So the correct sentence would be: ““I haven't been to New York before and neither has my sister.” So, the error is in Part C of the sentence. Hence, Option C is the correct answer.