What type of clause is shown in the parentheses carla had left a message on answering machine about whomever you spoken to?

The clause in parentheses, "(about whomever you spoken to)," is a noun clause.

Here's why:

* It functions as the object of the preposition "about." The entire phrase "about whomever you spoken to" tells us what Carla's message was about.

* It contains a subject ("whomever") and a verb ("spoken"). Even though it's not a complete sentence, it has the core elements of a clause.

* The word "whomever" is the subject of the clause. This means the clause is a noun clause because it acts as a noun, filling the object slot in the sentence.

Let me know if you'd like to explore other types of clauses!