Final answer:
The correct form of the verb leer is leyó.
Step-by-step explanation:
The correct form of the verb leer that best fills the blank in the sentence is leyó. This is because the subject él (he) is singular and in the past tense. The verb leyó is the conjugation of leer for the third person singular in the preterite tense.
Learn more about Verb conjugation in Spanish