Make their own food by extracting compounds from the ocean.
cyanobacteria
photoautotrophs
cemoautotrophs

Chemoautotrophs make their own food by extracting compounds from the ocean.

Chemoautotrophs are organisms that obtain their own food (energy) from inorganic chemical compounds such as sulfur, ferrous iron, hydrogen sulfide and ammonium in their environment.  These occur by chemosynthesis in which the organisms use chemical energy to produce carbohydrates. Chemoautotrophs are usually found in hostile environments such as at the bottom of the ocean or in acidic hot springs. Examples of chemoautotrophs include; thermoacidophiles, methanogens, nitrifiers and halophiles.

c. is the correct answer