What type of sentence has three commas in it?

There's no specific type of sentence defined by having three commas. The number of commas in a sentence depends on its structure and the need for punctuation to clarify meaning.

Here are some possibilities for why a sentence might have three commas:

* Appositives: A sentence might have three commas if it contains three appositives (phrases that rename or explain a noun). For example: "The dog, a fluffy golden retriever, the cat, a sleek black Persian, and the rabbit, a tiny brown bunny, all lived happily together."

* Lists: A sentence with a list of three or more items could have three commas separating them. For example: "The cake was decorated with chocolate chips, sprinkles, and whipped cream."

* Parentheticals: A sentence might have three commas if it contains three parentheticals (phrases that add extra information but aren't essential to the main sentence). For example: "The concert, which was held in the park, was a great success, even though it rained, and everyone had a good time."

It's important to remember: The number of commas in a sentence is not a defining characteristic. The most important thing is that the commas are used correctly to clarify meaning and improve readability.