Final answer:
The appropriate personal pronoun to fill in the blank is 'les.'
Step-by-step explanation:
The appropriate personal pronoun to fill in the blank in the sentence is les. The sentence translates to 'The students are important to them.' In this case, 'los estudiantes' is the subject of the sentence, and 'les' is the correct pronoun to indicate that the students are important to someone else.
Learn more about Personal pronouns in Spanish