Final answer:
The verb 'miras' is the correct choice to fill in the blank.
Step-by-step explanation:
The correct verb to fill in the blank in the sentence is miras.
The subject of the sentence is usted, which is the formal singular form of 'you' in Spanish. When an action is being done by 'usted', the corresponding verb form used is third person singular. The conjugated form of the verb 'mirar' (to watch) in third person singular is miras.
Therefore, the correct sentence is: Usted miras la televisión todos los días.
Learn more about Spanish Verbs