Final answer:
The correct form of the verb buscar is 'busqué.'
Step-by-step explanation:
The correct form of the verb buscar that best fits the sentence is busqué.
In the sentence, the subject 'yo' indicates that the correct form of buscar should be conjugated for the first person singular. 'Busqué' is the past tense conjugation of buscar for the first person singular, which matches the subject 'yo.'
Example: Ayer busqué las llaves por toda la casa.
Learn more about Verb conjugation in Spanish