The only option that is not a dependent clause is C. She slept until noon.
A dependent clause is a group of words that has a subject and a verb but cannot express a complete thought by itself. It needs an independent clause to complete its meaning.
Option A, "Since it was her favorite T-shirt," is a dependent clause because it begins with a subordinating conjunction ("since") and cannot express a complete thought by itself. We need to know what the person did with the T-shirt to understand the complete meaning.
Option B, "Because I was hungry," is also a dependent clause because it begins with a subordinating conjunction ("because") and cannot express a complete thought by itself. We need to know what the person did because they were hungry to understand the complete meaning.
Option D, "After it stops raining," is a dependent clause because it begins with a subordinating conjunction ("after") and cannot express a complete thought by itself. We need to know what will happen after the rain stops to understand the complete meaning.
However, option C, "She slept until noon," is an independent clause. It has a subject ("she") and a verb ("slept") and expresses a complete thought by itself. We do not need any additional information to understand the meaning of this sentence.
Therefore, the only option that is not a dependent clause is C. She slept until noon.