<h2>Right answer: visitaron
</h2>
This is a sentence written in simple past tense. We are able to know this because of the word ayer (yesterday).
Note, in spanish (castillian) the <u>Simple Past Tense</u> is used to express specific actions completed or concluded in the past that are separated from the present.
This means, it is applied when the person speaking gives information about the past that is not related to the present.
Now, the subject in the sentence is mi prima y mi hermano (my cousin and my brother) which is the <u>3rd person in plural</u> ellos (they). Hence the correct conjugation of the verb visitar (to visit) in past with this subject is visitaron (they visited), and the complete sentence is:
<h2>Ayer, mi prima y mi hermano <u>visitaron</u> la biblioteca municipal. </h2>
Yesterday, my cousin and my brother <u>visited</u> the municipal library.
The other options are<u> incorrect </u>because:
-visité (I visited) although is conjugated in simple past, it is written with the <u>1st person in singular</u> yo (I). Thus, it does not match with the subject of the sentence.
-visitan (they visit) is written in present tense with the <u>3rd person in plural</u> ellos (they).
-visitó (he/she visited) although is conjugated in simple past, it is written with the <u>3rd person in singular </u>él/ella/eso/esa (he/she/it). Thus, it does not match with the subject of the sentence.