Final answer:
The correct subject pronoun to address a professional in Spanish is 'usted'.
Step-by-step explanation:
The correct subject pronoun to address a professional in Spanish is usted. In the given statement, the correct way to address a professional named Sr. Pineda would be by using usted. For example, the correct sentence would be: "¿Es optimista o pesimista, Sr. Pineda? Usted".
Learn more about Subject Pronouns in Spanish