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 'A los estudiantes importan sus estudios' is les.
This is because the verb 'importan' agrees with the subject 'estudiantes' which is plural. The pronoun 'les' is used to indicate that something matters to a group of people.
For example, if we wanted to say 'The students care about their studies' in English, we would use the pronoun 'they', which is the equivalent of 'les' in Spanish.
Learn more about Personal pronouns in Spanish