What Did the Mars Rover Opportunity Discover on Mars That

Multiple Choice

What did the Mars rover Opportunity discover on Mars that relates to questions about the existence of water on Mars?

A) The rover found liquid water emerging from a spring,freezing to ice.
B) The rover found ice in the soil.
C) The rover found sedimentary rocks that contained minerals that could only have formed by precipitation from water.
D) The rover found no evidence of water ever having been on Mars.