In which one of the following countries was a peace accord signed recently to end a two-decade old civil war ?

The Comprehensive Peace Agreement (CPA), also known as the Naivasha Agreement, was signed on January 9, 2005, between the Government of Sudan and the Sudan People's Liberation Movement (SPLM) [t1][t2]. This historic accord was specifically designed to end the Second Sudanese Civil War, which had lasted for over two decades (1983–2005) and resulted in millions of deaths and displacements [t3][t4][t8]. The agreement established a framework for democratic governance, oil revenue sharing, and a timetable for a Southern Sudanese independence referendum, which eventually led to the creation of South Sudan in 2011 [t1][t5][t8]. While other countries like Colombia have also signed peace accords to end long-term conflicts, the specific 'two-decade' timeframe and the 'recent' context of the 2005 agreement (relative to the question's origin) point directly to Sudan [t4][t6].

Sources

1. [1] https://en.wikipedia.org/wiki/Comprehensive_Peace_Agreement
2. [2] https://www.govinfo.gov/link/plaw/108/public/497
3. [3] https://peacemaker.un.org/en/documents/2005-sudanese-comprehensive-peace-agreement
4. [4] https://www.cfr.org/global-conflict-tracker/conflict/civil-war-south-sudan