Below are two sentences. Which one of the following possibilities correctly combines them using an adjectival clause? John is a blues singer. John lives in Pittsburgh.

Answer:
John, who lives in Pittsburgh, is a blues singer.
Explanation:
Adjectival clauses commonly begin with words such as:
- Who
- Whom
- Whose
- That
- Which
In this case, you're using "Who" to combine the possibilities.