Which of these sentences is an example of paradox?
a. out of the frying pan, into the fire.
b. my argument is right because i said so.
c. through science, we will kill death itself.
d. money doesn't grow on trees, you know.

This one is the best example of paradox: c. through science, we will kill death itself. Because death can't be killed, it's nonsense.

A paradox is a statement that leads to something impossible, despite seemingly being logical. So, having this in mind, the paradox among these sentences is C. Through science, we will kill death itself, because there is (still) no way for humans to eliminate death, not even using the best technology and science there is.