Alejandro estudia para el examen.
The correct answer is the second one.
Spanish verbs have suffixes for each of the pronouns, just like English does (only for the third person singular). So, this is how you conjugate the verb estudiar in Spanish:
1. yo estudio 1. nosotros estudiamos
2. tu estudias 2. vosotros <span>estudiáis
3. el/ella/Usted estudia 3. Ellos/ellas/Ustedes estudian</span>
Yo soy in alumno
You estoy en clase de espanol
You soy muy feliz
You soy mue enteligente
You soy un buen amigo
1- se
2-nos
3-me
4-me
5-me
6-me
7-te
8-se
9-se
I hope it helps you:)