Answer: Now let's practice building some sentences in which we use the "preterite" past form of the verb to express a one-time event at a particular point of time in the past. I bought a gift (un Regalo) for my friend. Yo compré un Regalo para mi amigo(a). ... Mary bought a gift for her friend.
Explanation:
A.) El libro esta dentro de la mochila is the answer.
Hope it helped!!
I cant read spanish but i will try to translate and help :)