Answer:
![\boxed {\tt Leen}](https://img.qammunity.org/2021/formulas/spanish/high-school/cfd6qwbidt3m4e0lo480mao2dmak1nsqsp.png)
Explanation:
First, let's translate the sentence.
Lara y Beatriz _____ en la biblioteca ⇒ Lara and Beatriz ____ in the library.
We want to fill in the blank with the correct form of the verb: leer
To conjugate a verb, drop the ending, then add on the correct ending.
1. Drop the ending
Get rid of the -er ending.
Leer ⇒ le
2. Add the correct ending.
We are conjugating for Lara y Beatriz. They are two people, so we should conjugate for ellos/ellas/ustedes. The verb ending for ellos/ellas/ustedes for -er verbs is en.
Le ⇒ leen
The correct answer is C. leen. The completed sentence is:
Lara y Beatriz leen en la biblioteca ⇒ Lara and Beatriz read in the library.