Why do donuts have holes?

This seemed like a pretty easy question to answer, but it isn't. Too bad there isn't some prehistoric system memory somewhere with the answer. According to wikipedia there are three possible explanations:

• Introduced by Dutch settlers to North America called olykoeks (oily cakes). There is evidence that pastries were prepared in the southwest by prehistoric Native Americans.

• Hansen Gregory claimed to have invented donuts in 1847 at sea. I guess regular donuts had a raw center so he claims to have just punched a hole through it with a pepper box.

• In the book Farmer Boy by Laura Ingalls Wilder's there is mention of a "new fangled" donut. The braided ones turn over when cooked, but the ring ones have to be turned over.

I guess we will never really know why donuts have holes, but I'm glad they do because I love eating donut holes, they just taste healthier than regular donuts.