Final answer:
The subject of the sentence is 'Tú' and the correct verb form is 'eres'.
Step-by-step explanation:
The subject of the sentence is 'Tú', which means 'you' in Spanish. The verb that agrees with this subject is 'eres', which means 'are' in the second-person singular form. Therefore, the correct answer is Option A: eres.
Learn more about Spanish verb conjugation