Which among the ff. is the best hypothesis and why

Question

-Cans were painted different colors and filled with water. They were exposed to sunlight to determine the temperature of each can.

a.If the color of the can in dark-based, then the temperature of the water inside it will rise.

b.If the color of the can is light-based, then the temperature of the water inside it will retain.

c. If the cans were painted different colors, then the temperature of the water in each can will differ.

I'm unsure if the answers could be both, only one, or none. If there are none that fit the proper hypothesis or there is something to include (if ___ then ___), please state it. Thanks!

Answer 1

I believe that the answer is all of the above, but only in a case where the sun is shining.  The idea is that the darker paint will attract more sunlight, which would heat the water in that particular can to a higher temperature.  However, if it's a cloudy day, I don't think the darker paint on the cans could attract sunlight to raise the temperature of the water.  

Answer 2

Some of them are correct with the same thoughts and meanings. Only c. is wrong. But for me, the best answer is a., because it tells the thought directly.