That's how the Dutch electoral system works, based on...

That's how the Dutch electoral system works, based on proportional representation. The leader of the VVD is deemed to be the 'informateur' as they are the senior statemen who is most likely to form a coalition. The exact shape of the coalition will still take some time to finalise.

Incidentally, in one of early episodes of Borgen, there was a great episode which focused on coalition building in a PR system.