A relevant post from the pit thread on the Trump admin:
http://boards.straightdope.com/sdmb/showpost.php?p=21817742&postcount=35675
In case anyone else is confused why “No, he’s just not going to get Greenland” isn’t an option listed.
Anyways, I’m going with option D: “Trump is crazy but he’s not about to declare war on the EU over a random pronouncement like this”. And I will gladly take bets on that.