There are generic MBAs that give you a general background in the basics of economics, marketing and financial concepts to which students can add between 3 - 5 classes to obtain an area of concentration or major. There are still other MBA programs that go beyond the functional or industrial specialization offered through a traditional area of specialization or major. These specialized MBAs take an in-depth approach to a particular business function area, such as banking or finance, or may focus on an industry such as oil and gas or aviation.
When looking for an MBA, consider if you know exactly where you want to end up, and that will help guide you in terms of how specific a degree to take. Alternately, if you want to be able to keep all your options wide open, consider studying in a more general program.