Final answer:
The subject of the sentence is 'yo' (I) and the correct verb to describe the subject's current state is 'estoy' (am).
Step-by-step explanation:
The subject of the sentence is the pronoun 'yo' (I). The verb 'estoy' (am) is used to describe the current state or condition of the subject, so 'estoy' is the correct option. Therefore, the correct answer is D. estoy.
Learn more about The verb 'estoy' (am) in Spanish sentences to describe the subject's current state