Final answer:
The correct Spanish word is 'están mirando'.
Step-by-step explanation:
The correct Spanish word to complete the sentence is están mirando.
Mis padres están mirando televisión.
In this sentence, the subject 'Mis padres' (My parents) is plural, so we use the plural form of the verb 'estar' (to be), which is 'están.' 'Mirando' is the present participle of the verb 'mirar' (to watch), which agrees with the subject and means 'watching'.
Learn more about Spanish verb conjugation