What significant change did the St Andrews Agreement introduce regarding the roles of the First Minister and deputy First Minister?

The St Andrews Agreement introduced a crucial change by stating that both the First Minister and deputy First Minister would be appointed from the largest party in each community. This adjustment was aimed at ensuring a more balanced representation of Northern Ireland's diverse political landscape, particularly in relation to the divisions between Unionism and Nationalism.

By allowing the two roles to be filled by representatives from the largest parties in respective communities, it reinforced the principle of power-sharing and cooperation between different political factions. This change was significant in fostering a more inclusive governing structure, reflecting the complex social and political fabric of the region, and aimed to promote stability in a post-conflict society.

The other options refer to various electoral mechanics and representation strategies, but they do not capture the essence of the St Andrews Agreement's focus on shared leadership across community lines.