Answer:
It has a new store that sells superhero and manga comics.
Step-by-step explanation:
An adjective clause is a subordinate (also called dependent) clause that modifies a noun or a pronoun in a complex sentence (a sentence consisting of an independent clause and one or more dependent clauses). An adjective clause almost always comes right after the word it modifies.
The sentence that contains an adjective clause is the fourth one: It has a new store that sells superhero and manga comics.
The independent clause is It has a new store.
The adjective clause is That sells superhero and manga comics. It describes the word store (What kind of store? The one that sells superhero and manga comics).