What color is Crown Prince Willem-Alexander of the Netherlands associated with?

Explanation

From birth Willem-Alexander, the Crown Prince of the Netherlands, had three titles: Prince of the Netherlands (Dutch: Prins der Nederlanden), Prince of Orange-Nassau (Dutch: Prins van Oranje-Nassau), and Jonkheer of Amsberg (Dutch: Jonkheer van Amsberg). He married Princess Máxima in 2002. Togethey, they have three daughters: Princess Catharina-Amalia (born 2003), Princess Alexia (born 2005), and Princess Ariane (born 2007).