Final answer:
The correct preterite form of the verb 'organizar' to fill in the blank in the sentence is 'organizó'.
Step-by-step explanation:
The correct preterite form of the verb 'organizar' to fill in the blank in the provided sentence is option B. 'organizó'. The sentence should read:
La asociación de estudiantes organizó un baile de fin de curso.
Learn more about Verb conjugation in Spanish