The Basque separatist organisation is active in

The Basque separatist movement is centered in the Basque region of Spain; the area is described as a hilly, prosperous region recognised as an autonomous region within Spain whose nationalists have sought full separation and have at times used violent means to press that demand [1]. Separatist activity by the Basques is specifically located in northern Spain (and adjacent areas) as noted in comparative discussions of global separatist movements [2]. Contemporary analyses and backgrounders identify ETA (Euskadi ta Askatasuna) as the Basque separatist organization that carried out its campaign primarily in the Basque regions of Spain (with cross-border implications) to pursue independence [3]. Therefore the correct answer is Spain.

Sources

1. [1] Political Theory, Class XI (NCERT 2025 ed.) > Chapter 7: Nationalism > DEMAND FOR NATIONAL SELF-DETERMINATION IN BASQUE > p. 105
2. [2] Political Theory, Class XI (NCERT 2025 ed.) > Chapter 7: Nationalism > p. 99
3. [3] https://www.cfr.org/backgrounder/basque-fatherland-and-liberty-eta-spain-separatists-euskadi-ta-askatasuna