3. (b) That's right. The right to an action for nuisance belongs to the person who is entitled to possession of the property in question. This means that it would not matter if A was the tenant rather than the owner of the apartment.

Who is liable? The person who is creating the nuisance. In the case of the noise from the factory, this would be the occupier of the factory. An occupier must take reasonable steps to stop a nuisance they know (or should know) about.