Final answer:
The word that best completes the sentence is 'Se rellenan'. It means 'are stuffed' in English.
Step-by-step explanation:
The word that best completes the sentence is Se rellenan. The sentence translates to 'The peppers are stuffed with minced meat or cheese.' The verb 'rellenan' means 'are stuffed' and matches with the plural noun 'los pimientos'.
Learn more about Spanish verb conjugation