As Oceans Acidify, Carbonate Ions in the Ocean

As oceans acidify, carbonate ions in the ocean:

A) become more abundant and more available to organisms that build calcium carbonate skeletons.
B) become less abundant and less available to organisms that build calcium carbonate skeletons.
C) become more abundant, but less bioavailable to organisms that build calcium carbonate skeletons.
D) become less abundant, but more bioavailable to organisms that build calcium carbonate skeletons.
E) remain as available to organisms that build calcium carbonate skeletons as they were before oceans acidified.