<h2>Right answer: recibiste
</h2>
This is a conversation between two persons, Carla and Jaime.
Where Carla makes a question in past, we know this because of the word ayer (yesterday) at the beginning of the sentence and because the verb mandar (to send) is written in past as mandé (I sent):
<u>Ayer</u> te <u>mandé</u> un correo electrónico (Yesterday I sent you an email)
Now, if you send something to someone, that thing must be<u> received.</u> Therefore, the correct verb is <u>recibiste</u> in past.
The complete conversation is:
<h2>
Carla: Ayer te mandé un correo electrónico. ¿(Tú) Lo <u>
recibiste</u>
?
</h2>
Yesterday I sent you an email. Did you receive it?
Jaime: Sí, recibí tu correo electrónico.
Yes, I received your email
The options mandaste (you sent), recibieron (you received - in plural) and mandaron (you sent - in plural) are <u>incorrect</u> because although are in past tense they do not match with the personal pronoun of the sentence, which is tú (you).