Answer:
The sentence that uses commas correctly is "My favorite flavors of ice cream are chocolate, strawberry, and butter pecan."
Step-by-step explanation:
There are many uses of commas, in this sentence the use of commas is to separate items in a series, we have the flavors of ice cream as elements in a list, the correct way to separate them is to use a comma in between every one of them starting right after the first element of the list and adding the las comma between the two elements along with the word and.