Luis: ¿a qué hora puedo ir al hospital?
recepcionista: a las once de la mañana.
a. vienes
b. vengo
c. venga
d. vengan

The right option that fills the blank is:

- Luis: ¿A qué hora puedo ir al hospital?

- Recepcionista: Venga a las once de la mañana.

Explanation:

The translation of the conversation is:

- Luis: What time can I go to the hospital?

- Receptionist: Come at eleven in the morning.

When information is requested from a person and that person gives the exact indications, the imperative form of the verb must be used, in this case, the verb "venir", which conjugation in the mentioned form is:

Although in the second sentence the personal pronoun does not appear since it is tacit, the personal pronoun is "usted" (addressing the second person, without having any confidence with it) and the correct form of the imperative that applies to that pronoun is "venga".