Help choose an upper division elective.

I'm graduating this year and have a job lined up at an Asset Management firm already (though I don't know what I want to do long term). I'm majoring in economics and can take either an upper div econ course (international finance) or a lower div math course (linear algebra). I don't really need either to help me graduate and am just taking them out of intellectual curiosity. If I take linear algebra this quarter, I can take lower div differential equations next quarter.

What do you guys recommend?