Which sentence uses commas to correctly separate items in a series? Douglas packed his suitcase for the audition, with two pairs of pants, four shirts, several pairs of socks and his trumpet.

Jerry filled his backpack with a change of clothes, a flashlight his sleeping bag, snacks and water for his hike in the mountains.

Kiera loaded up her bag with her camera, two different lenses, and extra rolls of film, for her nature photography class.

Ashley packed a bathing suit and wrap, sunscreen, sun hat, sandals, and a good mystery book for her day at the beach.

The third sentence applies the usage of commas well

Explanation:

coz...

Douglas packed his suitcase for the audition, with two pairs of pants, four shirts, several pairs of socks and his trumpet. ---> a comma should've been used, corrected version--> ...of socks, and his trumpet

Jerry filled his backpack with a change of clothes, a flashlight his sleeping bag, snacks and water for his hike in the mountains.

For this sentence, the comma should have been used between flashlight and his sleeping bag---> the corrected version would be-a flashlight, his sleeping bag, snacks and water for his hike in the mountains.

Ashley packed a bathing suit and wrap, sunscreen, sun hat, sandals, and a good mystery book for her day at the beach.---> A comma could have been used here instead of "and"

so ya, here's the ans...hope it helps!  

easy - boys have problems.

i hope this ! (: