Answer:
I think its Barnacles attach to a whale
Commensalism means one is helped while the other is neither helped nor harmed
Step-by-step explanation:
A. - Lion gets food while antelope dies (one help, other harmed)
B. - Humming bird gets food while flower helps get reproducing (both helped)
C. - Wolf and fox fight for same prey (Either one is helped and one is harmed or both lose the prey and neither are helped)
D. - Barnacles stick to whale
Heres are quotes on barnacles and whales,
"The barnacles are just along for the ride. They don't harm the whales or feed on the whales, like true parasites do. Barnacles don't serve any obvious advantage to the whales, but they give helpful lice a place to hang onto the whale without getting washed away by water."
"Whale barnacles typically attach to baleen whales and have a commensal relationship–the barnacle benefits and the whale is neither helped nor harmed. "
So your answer may be D