It's more than enough for Office 2011, or Office 2010 in Windows 7 through Boot Camp. It depends on whether you need it to last 4 years, though. If so, it might seem hopelessly out of date in 2015, though to be fair, so would the 13" MacBook Air or current 13" MacBook Pro (perhaps slight less out of date). Excel, PowerPoint, and Word (the most common applications in your business classes) don't need much horsepower but if the next versions have a lot of bloat they could slow down a bit.
The 13" MacBook Air is pretty portable, too, so don't rule out that one. Either way, I'd definitely suggest getting the 4GB version, and if you are getting the 11" version, go with the 128GB SSD. You might find yourself using more space over time than you realize, particularly if you need to install Windows at some point.