Answer:
D. Our gourmet bread was a wonderful complement to the delicious cheese.
Step-by-step explanation:
Option A is not correct because the term "complement system" refers to a part of the immune system that brings about the lysis, or destruction, of foreign or damage cells. Option B is also wrong because "a subject complement" refers to a part of speech or of a a sentence. And, likewise, option C is also wrong because "full complement" refers to the number needed to make up a whole force.
On the other hand, option D does use the definition of complement as something that fills up, completes, or makes perfect. This sentence conveys that the gourmet bread completed and brought to perfection the delicious cheese. Without the gourmet bread, the cheese would not taste the same.