In which sentence does the underlined objective complement function as a noun? the band director thought jake wise for practicing and taking lessons before his audition. mr. orland considered grace's tuba-playing skills stellar. the director appointed cameron leader of his section?

The correct answer is C. The director appointed Cameron leader of his section.
In order to find the object complement (a word or phrase which completes an object), we first have to find the object. In sentence C, the object is Cameron (who did the director appoint? - Cameron). The phrase that completes the object and acts as its complement is leader of his section (What did he appoint Cameron as? - Leader of his section). As you can see, leader is a noun (as opposed to wise and stellar in sentences A and B which are adjectives), which means that C is correct.

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