Answer :
The sentence that uses commas and quotation marks correctly is
D. "You will need a jacket," Nate said, "if you're going outdoors."
A. is wrong because there should be quotation mark after (jacket,) and also a quotation mark before (if)
B. is wrong because there should be a comma after (jacket)
C. is wrong because there should be quotation mark after (jacket,) and a comma after (said)
Hope this helps. :)