Answer:
The correct answer is relative clause.
Step-by-step explanation:
This sentence is a relative clause because it's describing "the town". In the sentence, "where I grow up" is an adjective for "the town", but it can't be used as the noun, like "where I grow up is extremely small", because we're not sure if the sentence is talking about a city, a house, a school, a room, a garden or somewhere else.