When an initiative proposal and an alternative proposal are put to the vote on the same day, what choices does the voter have?

Law 24.747 onAgenda initiative (1996-11-27) [Ley 24.747 Iniciativa legislativa popular]

http://www.mininterior.gov.ar/asuntos_politicos_y_alectorales/dinap/dinap_archivos/INICIATIVALEGISLATIVAPOPULAR-Ley24.747.pdf

Law 25.432 onReferendum (2001-05-23) [Ley 25.432 Consulta popular vinculante y novinculante]