This exercise stands for two different problems. Let's solve each as follows:
1. FIRST PROBLEM:
Here we need to fill in the blank with the correct word. The blanks must be filled with a corresponding Direct Object Pronoun. A Direct Object is a noun that receives, in an direct way, the action of a verb and the Direct Object Pronoun replaces the direct object. The Table below shows the different direct object pronouns. So we have five (5) blanks and they will be filled as follows:
Sofía ve a Armando en la calle. Él no la saluda porque no la reconoce. No hablan desde hace mucho tiempo. Armando terminó sus estudios en 2001, y Sofía los terminó en 2002. Tampoco hablan mucho con sus otros compañeros de clase. De hecho, Armando nunca los llama. Sólo habló por teléfono con Sofía una vez porque ella lo llamó. Así que ambos siguen su camino
Thus, we have the correct options:
(1) la - Here we use la because Sofía is the direct object, so we replace her by the direct object pronoun for the third person singular in feminine form, which is la.
(2) la - We also use la here because Sofía continues to be the direct object.
(3) los - Here we use los because estudios is the direct object, so we replace it by the direct object pronoun for the third person plural in masculine form, which is los.
(4) los - Here we use los because compañeros is the direct object, so we replace it by los.
(5) lo - Here we use lo because Armando is the direct object, so we replace him by the direct object pronoun for the third person singular in masculine form, which is lo.
2. SECOND PROBLEM:
In this second problem, we must give an answer to the corresponding question. Therefore, we have the following dialogues:
First.
¿Ya abriste la correspondencia?
Sí, ya la abrí.
We choose Sí, ya la abrí, because in the question the direct object is correspondencia (feminine singular noun), so we replace it in the answer by the direct object pronoun for the third person singular in feminine form, which is la.
Second.
¿Puedes leer este cuento?
Sí, puedo leerlo.
We choose Sí, puedo leerlo, because in the question the direct object is cuento (masculine noun), so we replace it in the answer by the direct object pronoun for the third person singular in masculine form, which is lo. It's also valid to attach the direct object pronoun after an infinitive verb (verbs ending in ar, er, ir)
Third.
¿Quieres describir las fotos?
No, no las quiero describir.
We choose No, no las quiero describir, because in the question the direct object is fotos (feminine plural noun), so we replace it in the answer by the direct object pronoun for the third person plural in feminine form, which is las.
Fourth.
¿Comprendes la lectura?
Sí, la comprendo.
We choose Sí, la comprendo, because in the question the direct object is lectura (feminine singular noun), so we replace it in the answer by the direct object pronoun for the third person singular in feminine form, which is la.
Fifth.
¿Tienes los pasajes?
No, no los tengo
We choose No, no los tengo, because in the question the direct object is pasajes (masculine plural noun), so we replace it in the answer by the direct object pronoun for the third person plural in masculine form, which is los