Question

Mi hermana ______ da la llave (the key) a ti

Answer 1

The right answer is te

Mi hermana te da la llave a ti

te is the indirect object pronoun for the second-person singular. An indirect object pronoun (un pronombre de objeto indirecto) is a person that receives the action of a verb indirectly. It tells us to whom or for whom something is done. Therefore, my sister is carrying out an action, that is, she's giving you the key.

Answer 2

Mi hermana te da la llave a ti.