The correct option is B Who
Option B: 'Who' refers to a person, and is relevant here. The given question also asks about a person who "lives in that old house". Hence option B is correct.
Option A: 'What' asks about some thing, rather than some person.
Option C: 'Which' is used when a choice is presented between two things. In the given question, there isn't any choice.
Option D: 'How' asks about the manner or way something is done. This word is hence not relevant here.
So, options A, C and D are incorrect.