Without Microbes (Primarily Bacteria), What Would Most Likely Happen to the World's

Multiple Choice

Without microbes (primarily bacteria) , what would most likely happen to the world's natural nitrogen cycle?

A) Cycling would stop; most nitrogen would remain in the atmosphere as N₂ gas.
B) The cycle would continue unchanged; chemical reactions would take over bacterial actions.
C) Nitrogen cycling in the oceans, which does not involve bacteria, would become dominant.
D) The cycle would continue unchanged; bacterial activity is not needed now that humans can fix nitrogen.
E) Nitrogen fixation would not occur, but nitrification and denitrification would remain unchanged.