What major event contributed to the rise of Sinn Féin?

The Good Friday Agreement significantly contributed to the rise of Sinn Féin by establishing a political framework that allowed the party to transition from primarily a nationalist movement focused on armed struggle to a legitimate political force in Northern Ireland. The 1998 Agreement acknowledged the aspirations of Irish nationalists and created a more inclusive political environment in which Sinn Féin could operate.

As aspects of communal conflict were addressed through the peace process, Sinn Féin was able to present itself as a key player in the negotiations, gaining credibility and support. The Agreement facilitated power-sharing arrangements and increased the party's appeal among a broader voter base, allowing Sinn Féin to gain seats and influence in government.

The other options, while impactful in various ways, do not have the same direct correlation to Sinn Féin's rise as the Good Friday Agreement. The Republic's economic boom led to improvements in the economy but did not specifically advance the party's status in Northern Ireland. Increased youth participation and social media campaigning are more about dynamics of modern campaigning strategies and civic engagement but do not fundamentally underscore a pivotal moment like the Agreement did for the party's growth and legitimacy in the northern political landscape.