In Spanish, there are five indirect object pronouns. They all have different meanings, lining up with pronouns.
Me = to me, for me, me (Yo)
Te = to you, for you, you familiar (Tú)
Le = to you formal/her/him, for you formal/her/him, you formal/her/him (Usted, Él, Ella)
Nos = to us, for us, us (Nosotros)
Les = to you formal plural/they masculine/they feminine, for you formal plural/they masculine/they feminine, you formal plural/they masculine/they feminine (Ustedes, Ellos, Ellas)
Using this information, we will fill in the blanks.
Answer 1:
Nosotros <u>C. LE</u> dimos los libros usados al profesor.
-> Translates to about "We ________ gave the used books <em>to the teacher</em>."
-> In this case the teacher is an él, or he. This means we will use le
Answer 2:
Mi profesora de ciencias <u>A. ME</u> dice a mí que es necesario recoger la basura en las calles.
-> Translates to about "My science teacher _____ tells me that it is necessary to collect garbage in the streets."
-> We will use (A. me) as "me" is receiving the action
<em>What are indirect object pronouns?</em>
<em> An </em><em>indirect object pronoun</em><em> is used instead of the noun to show the person or thing receiving an </em><em>action</em><em>.</em>