A compliance administrator at Contoso is configuring sensitivity labels in Microsoft Purview. They create three labels: 'Public', 'Confidential', and 'Highly Confidential', arranged in that order from top to bottom in the label list. A user accidentally applies both 'Public' and 'Highly Confidential' at different times to the same document, and the administrator wants to understand how label priority affects protection. In the Purview sensitivity label ordering, which label is considered the highest priority (most restrictive) when interpreting the list?