In the sentence 'They demolished the house WHERE I USED TO LIVE', what is 'WHERE' grammatically?

• A. Relative adverb introducing a place clause
• B. Relative pronoun introducing a defining clause
• C. Preposition in a prepositional phrase
• D. Conjunction linking clauses

Answer: (A)

The key idea is that this use of where expresses location and links a clause to a noun. Here, where introduces a clause that modifies the noun phrase “the house,” giving information about its location: “the house where I used to live.” That makes where a relative adverb introducing a place clause. It’s the same idea as saying “the house in which I used to live,” but where condenses the prepositional link into a single word.

So this isn’t a relative pronoun (which would refer to a person or thing) and it isn’t a standalone preposition or a conjunction. It functions as a relative adverb that introduces the clause about location.