In rugby union's Six Nations Championship, which of these teams cannot win the Triple Crown?

In rugby union, the Triple Crown is an honour contested annually by the "Home Nations" – i.e. England, Ireland, Scotland, and Wales who compete within the larger Six Nations Championship. If any one of these teams defeats all three other teams, they win the Triple Crown.

The Six Nations Championship also includes France and Italy, but their involvement in the tournament has no influence on the result of the Triple Crown, although it means that the winners of the Triple Crown are not necessarily the winners of the Championship as a whole.

Traditionally the Triple Crown was an informal honour with no trophy associated with it. However a trophy now exists, which has been awarded to Triple Crown winners since 2006.