Final answer:
The conjugations/forms of 'ser' in Spanish must match its pronoun.
Step-by-step explanation:
The correct answer is C. match.
When conjugating the verb 'ser' in Spanish, the forms must match the subject pronoun. For example, the form of 'ser' for 'yo' is 'soy', for 'tú' is 'eres', for 'él/ella/usted' is 'es', and so on.
Matching the conjugations of 'ser' with the subject pronouns is important to ensure grammatical correctness in Spanish sentences.
Learn more about Conjugation of 'ser' in Spanish