The most accurate way to describe the excerpt is to choose the option - it is a dependent clause. This means that something needs to be added - you need to finish the sentence so that it becomes an independent clause, and not a subordinate one.
Explanation:
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The Deep Magic<span> was a set of laws placed into Narnia by the Emperor-beyond-the</span><span>-Sea at the time of its </span><span>creation</span>
