Which of the Following Is MOST True of the Presence

Which of the following is MOST true of the presence of water on Mars?

A) There is no water, nor any evidence of water, on Mars.
B) There is evidence that suggests that there may have once been water on Mars, but no water remains.
C) There is evidence that suggests that liquid water may have existed on Mars, and the presence of water as ice has been discovered in the subsurface.
D) Liquid water has been discovered on the surface of Mars.