I am first year economics student and for the past month we have had it constantly drilled into us that all choices have an opportunity cost and thus they are all necessitated by scarcity. Thus when I saw this quesiton in my homework I was baffled.
I don't need an exact answer to this, but a hint would be great. My current line of thinking is leaning towards infinite resources like the sun, but I simply can't work it out. Thanks.