A. In art negative space refers to the area around an object (the background.) For example, In the left side of this image the negative space would be the white as it is the area around the object.
B. I found the negative space for this piece by looking at what my main subject was. That helped me know that the area around that (the background) was the negative space.
C. Negative space can help an artist make their main subject stand out/draw attention to it.
D. It enhances the image by giving attention to a single subject and making the image simple.