Select the letter of the choice that identifies the function of the word

or phrase in quotes in the following sentence:
Rock hounds "treasure rocks called geodes".
a. simple subject
b. simple predicate
c. complete subject
d. complete predicate

c. complete subject

The function of the phrase "treasure rocks called geodes" in the sentence "Rock hounds 'treasure rocks called geodes'" is:

c. complete subject

The complete subject of the sentence is "Rock hounds treasure rocks called geodes," which includes the subject "Rock hounds" and the descriptive phrase "treasure rocks called geodes."