Answer:
The relative/adjective clause is "that you mentioned".
Explanation:
An adjective clause is a dependent clause that acts as an adjective, modifying or describing a noun in a sentence. It is also known as a relative clause.
In the given sentence "the book that you mentioned is no longer in print", the dependent clause is "that you mentioned". The sentence can also stand as a complete sentence without the dependent clause:
"The book is no longer in print."
But with the dependent clause, we are given more details about the book, describing the noun "the book".
Thus, the relative/adjective clause is "that you mentioned".
