If Earth's Oceans Are Carbon Dioxide Sinks,that Means That Carbon

If Earth's oceans are carbon dioxide sinks,that means that carbon dioxide should remain in oceans infinitely.Is that accurate?

A) Yes, the oceans are a sink and no carbon dioxide is ever released. This process explains ocean acidification.
B) No, the oceans are not sinks although they do assimilate carbon dioxide.
C) No, the carbon dioxide assimilated into the deep ocean in the Atlantic will eventually surface elsewhere and be released back into the atmosphere.
D) Yes, the oceans are a sink for carbon dioxide, but only in the Southern Indian and Pacific Oceans. In a few decades the carbon dioxide is assimilated by marine animals and released when they die.