Can somebody help me

they float because they are less dense than the water itself

something denser than water, like a rock, will sink to the bottom

c. live where it’s cold and icy

you didn't give any options but heres what i can tell you: an inference is likely to change based on additional observations. the latter is something that you have seen or sensed using your sensory organs while the former is like a conclusion out from what you have observed.