Which sentence uses commas correctly?
A.
Sea lions, seals and, dolphins are mammals that live in the ocean.
B.
Pickled herring, crisp bread, and potatoes are foods commonly eaten in Sweden, Norway, and Denmark.
C.
I enjoy hamburgers with ketchup, pickles, lettuce, and, a toasted bun.
D.
Caribbean flamingos live in lagoons eat mollusks and have bright pink plumage.