Question: Which of the founder of Basque artistic group was a Spanish Basque sculptor?

Context paragraphs:
Basque Socialist Party: Basque Socialist Party or Basque Socialist Assembly (Spanish: "Partido Socialista Vasco" and Basque: "Euskal Sozialista Biltzarrea" ; ESB–PSV) was a socialist Basque political party, with presence in the Spanish Basque Country.  The party was illegal until 1978.

Iker: Iker is a Basque male given name.  The corresponding female name is Ikerne.  It was created by the Spanish Basque writer Sabino Arana in his book "Deun-Ixendegi Euzkotarra " ("Collection of Basque Saints' Names")—an effort to provide neologistic Basque versions of names instead of the traditional adaptations of Romance names.  The name may refer to:

Euskal Herriko Alderdi Sozialista: Euskal Herriko Alderdi Sozialista (English: Socialist Party of the Basque Country ; EHAS) was an illegal revolutionary socialist Basque political party, with presence in both Spanish Basque Country and the French Basque Country.

Gâteau Basque: Gâteau Basque is a traditional dessert from the Basque region of France.  Typically Gâteau Basque is constructed from layers of a wheat flour based cake (a butter-sugar pastry dough, in this case "pâte sablée", not "brisée") with a filling of either almond or vanilla pastry cream, or preserved cherries.  The pastry cream Gâteau Basque is more typical in the Spanish Basque Country.  This started during the 19th century.

Basque Americans: Basque Americans (Basque: "euskal estatubatuarrak" ) are Americans of Basque descent.  According to the 2000 US census, there are 57,793 Americans of full or partial Basque descent, but the real number of Basque Americans could easily reach 100,000 people.  Of them, 41,811 people claimed be simply Basque American, 9,296 claimed be originating from Spanish Basque Country, and the other 6,686 claimed be originating from the French Basque Country.  The states with the largest Basque-American populations are California (20,868), Idaho (6,637), Nevada (6,096), Washington (2,665) and Oregon (2,627).

ETA (separatist group): ETA (] , ] ), an acronym for Euskadi Ta Askatasuna (] ; "Basque Homeland and Liberty"), is a formerly armed leftist Basque nationalist and separatist organization in the Basque Country (in northern Spain and southwestern France).  The group was founded in 1959 and later evolved from a group promoting traditional Basque culture to a paramilitary group engaged in a violent campaign of bombing, assassinations and kidnappings in the Southern Basque Country and throughout Spanish territory.  Its goal was gaining independence for the Basque Country.  ETA is the main group within the Basque National Liberation Movement and is the most important Basque participant in the Basque conflict.

Eduardo Chillida: Eduardo Chillida Juantegui, or Eduardo Txillida Juantegi in Basque, (10 January 1924 – 19 August 2002) was a Spanish Basque sculptor notable for his monumental abstract works.

Batallón Vasco Español: The Batallón Vasco Español (Basque Spanish Battalion) was a Spanish Basque right-wing paramilitary group active from 1975 to 1981, primarily in French Basque Country.

Gaur (artistic group): Gaur ('today' in Basque) was a Basque artistic group founded in 1966 by Amable Arias, Rafael Ruiz Balerdi, Nestor Basterretxea, Eduardo Chillida, Remigio Mendiburu, Jorge Oteiza, José Antonio Sistiaga, and José Luis Zumeta.  The avant-guard group, based in Gipuzkoa, Spain, provided the springboard for a wide Basque artistic movement with close links to influential social, cultural and political agents in the Basque Country opposed to Franco's dictatorship during the 70s and early 80s.

Jesús Guridi: Jesús Guridi Bidaola (25 September 1886 – 7 April 1961) was a Spanish Basque composer who was a key player in 20th century Spanish and Basque music.  His style fits into the late Romantic idiom, directly inherited from Wagner, and with a strong influence from Basque culture.  Among his best known works are the zarzuela "El Caserío", the opera "Amaya", the orchestral work "Ten Basque Melodies" and his organ works, where the "Triptych of the Good Shepherd" can be highlighted.

Supporting paragraphs: Gaur (artistic group) Eduardo Chillida
Answer: Eduardo Chillida