The 3rd one is the one that is correct
<span>Él es un compañero de clase is the right answer. The 1st sentence is ella but </span>compañero should be compañera. In the second one ella should not have an accent mark and in the last one el doesn't match with una.
Falso creo espero que sea bien
It is the second one because you are talking about you wanting to save money
To make the answering process easy let's first conjugate ser in its possible forms:
Yo- soy
Tu- eres
ella/ello/usted- es
nostros- somos
ellos/ellas/ustedes-<span> son
</span>So now you just have to identfy the sentence where both the noun/pronoun matches the verb conjugation.
Therefore the best answer would be <span>Clara no es cubana (option 2).
It could not be:
</span>1) "Ellas es muy inteligentes" because Ellas matches son
3) "Nosotros son amigos" because Nosotros matches somos
4) "Yo eres serio" because Yo matches soy<span>
</span>
