Middelbaar Algemeen Voortgezet Onderwijs (Middle general secondary education).
MAVO is a form of secondary education similar to HAVO. HAVO is one step "up" in the "hierarchy".
A MAVO education generally takes four years. The first is usually spent in a mixed MAVO/HAVO class, to give the students some insight to their potential and a little more time to choose.
In the third year, students are allowed to drop several courses, I'm not entirely sure how many. I'll try to find out soon.
By the fourth year, when the finals take place, there will be six courses left. Possible choices include: Dutch (mandatory), English (mandatory), French, German, Mathematics, Physics, Chemistry, Geography, Economics, and Biology.
Students can take final exams on level C or D. D being the higher of the two. At most three examinations may be done at C level. To proceed to the fourth year of HAVO, all examinations must have been done (and passed) at D level.
Last year they changed this to "VMBO", which is a conjuction of VBO and MAVO. Not much has changed, other than that there are now four levels (A, B, C, and D) to choose from for the exams, I believe. But by the time I hit the stumbit button, it may have been changed again. It's not my fault.