In this picture, which letter represents the geosphere a, b,c, d?

Jayden is taking a test. he has to write why scientists support the theory that life began near hydrothermal vents in the ocean. which point should he include in his answer? a. hydrothermal vents were closest to ocean surface, and therefore could receive oxygen. b. oceans were dry and only had water near the hydrothermal vents in the earlier ages. c. even today, all life forms are first born near hydrothermal vents and they later migrate to land. d. fossils of archeabacteria, which are early common ancestors, were found near hydrothermal vents.