Answer:
The sentence that correctly combines the sentences using an appositive is the following one: Angelo's mom worked as an aeditor for a publishing firm in New York City, the capital of the publishing world.
Step-by-step explanation:
An appositive is a noun or noun phrase that renames another noun right beside it. Nonessential appositives are always separated from the rest of the sentence with commas. In this case, the appositive "the capital of the publishing world" renames the noun New York City. The appositive phrase is nonessential since if it was removed, the sentence would still have the same meaning (see 1).
1) Angelo's mom worked as an editor for a publishing firm in New York City.