The correct option is B when
Conjunctions are words that link other words, phrases, or clauses together. Subordinating conjunctions join independent and dependent clauses. Subordinating conjunction can signal a cause-and-effect relationship, a contrast, or some other kind of relationship between the clauses. Common subordinating conjunctions are because, since, as, although, though, while, and whereas. These show relation in time, place or condition When is used 'at or during the time that something happened.' and means ‘at the time that’. Thus option c is correct. While is used "during the time that something happened”. Option A is incorrect as in the sentence it is mentioned that' ill find somewhere to live and then give you my address' .this sentence cannot be rewritten as' ill give you my address during the time that I find somewhere to live'. So is used for showing the consequence of something. Thus Option D can be ruled out. 'If' is used to talk about the result or effect of something that may happen or be true. This cannot be used as in the earlier sentence there is quite an assurance that'ill find somewhere to live' but 'if' is used in case of a probable condition. Thus option B is incorrect.