Suppose a friend says that we don't need to worry about the rising temperatures associated with global climate change. Her claim is that increased temperatures will make planktonic algae grow faster and that carbon dioxide (CO₂) will be removed from the atmosphere faster. According to her, this carbon will be buried at the bottom of the ocean in calcium carbonate shells. As a result, the amount of carbon dioxide in the atmosphere will decrease and global warming will decline. A) Primary producers usually grow faster when CO₂ concentration increases, but to date they have not grown fast enough to make CO₂ levels drop.B) Primary producers usually grow slower when CO₂ concentration increases, so to date they can't make CO₂ levels drop.C) Primary producers grow fast enough to make CO₂ levels drop even today.D) Primary producers don't remove CO₂ from the atmosphere.

In the given question, the person predicts that if CO₂ level in the atmosphere will be increased then the phytoplanktons will grow more and the atmospheric carbon will be absorbed and will be fixed.

This statement juts seem like assumptions and if we consider this as a hypothesis then the facts will not be in favour of this hypothesis.

In the present day, the CO₂ level has already increased but the plants are not been able to utilise the Carbon dioxide and reduce global warming as the carbon uses free carbon from the atmosphere only and not bound carbon.

Thus, Option-A is correct.