Sentence 3, I believe is your answer.
The correct answer is C. T<span>he 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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<span><span>By repeating the amount of time she has spent away from home</span></span>
