To complete the sentence, the correct verb is escribiste , which means 'you wrote.' This form is appropriate for addressing someone informally. The other options do not fit the context of writing a letter to a grandmother. ;
The correct verb to fill in the blank is escribiste , which means 'you wrote.' This choice suits the informal second-person singular subject 'tú.' Therefore, the complete question is: ¿Tú escribiste una carta a tu abuela?
;