Final answer:
The correct form of estar to fill in the blank is 'estoy' as it matches the subject 'Yo' (I). The sentence should be 'Yo estoy contenta.'
Step-by-step explanation:
The correct form of estar to fill in the blank is estoy as it matches the subject 'Yo' (I). When describing someone's emotion or state of being, estar is used to indicate temporary states. In this case, 'contenta' means 'happy' which is a temporary emotion. Therefore, the correct sentence is 'Yo estoy contenta.'
Learn more about Spanish verb conjugation