Apologies for the delay in response. Generally, choices should be unique. In your example, you have 3 attributes:
You should create a unique string to represent each neighborhood; one way to do that would be to give each city a unique value and add the neighborhood name (say, MA_Boston_A).
Given the relationships between state, city and neighborhood, you may also want to consider using cascading selects to make it easier to filter the choices - see Cascading and external selects—Survey123 for ArcGIS | Documentation and Cascading Selects and External Selects