There is a cost of attending a college. The money and time that you spend on your education is an opportunity cost. You could the same amount of money and time for something else. What else could you do? What kind of lifestyle could you choose? What carrier would you have? All of these questions bear the concept of opportunity cost in this context.
In international trade, an exchange rate is a number that is used to show the value of one currency compared to another.
I am pretty sure it's four. I looked it up, and I have a book I just looked through. Sorry if it's wrong! Have a good rest of 2016!
Out of the choices given, the one that indicates best the the conflict in Rome is political is the lion walking around the Capital. The correct answer will be A.