B&O cartridges are definitely MM types when it comes to choosing the preamp input. However, their output levels are typically somewhat lower than other manufacturer's MM cartridges have. Therefore, if you have a choice, you might want to pick a preamp that has adjustable level, or be prepared to crank up the volume a little compared to other sources (the difference is nothing dramatic, though).
I would prefer a preamp with a DIN input connector, which would save you from an extra adapter in the very low level signal path, and the hassle of rigging up the grounding wire (please do not bastardize the original DIN cable!). However, these are pretty rare.