A tradeoff exists between two economic goals, X and Y. This tradeoff means that..?
A. X causes Y.
B. X and Y are equal.
C. getting more of X requires getting more of Y.
D. getting more of X requires getting less of Y.
A tradeoff means just what the name suggests. That to get one thing, you need to trade it in for another. Hence if I wanted more of X I'd have to trade in some of my rights to Y to get it. Therefore, getting more of X requires getting less of Y and vice versa.
Economics is all about tradeoffs :)
Always a good job right here. Keep rollnig on through.