If All Terrestrial Autotrophs Were Removed from the Planet, How

Multiple Choice

If all terrestrial autotrophs were removed from the planet, how would this alter the rate of carbon cycling on Earth?

A) The rate of carbon cycling would remain the same because microorganisms would liberate carbon faster into the atmosphere.
B) The rate of carbon cycling would decrease because the link between primary consumers and primary producers would be eliminated.
C) The rate of carbon cycling would decrease because there could be no terrestrial animals without plants supporting higher trophic levels.
D) The rate of carbon cycling would increase because marine primary producers would be able to use all the sunlight and not have to compete with terrestrial plants for light.