Carlos / preferir / las papas fritas

First, you would need to conjugate preferir.

To do this you would need to remove the -ir and add an e since since it is in present tense and you are speaking for Carlos. This means that it would be in the tú form.

Carlos prefere las papas fritas.

Carlos prefers french fries.

Hope this helps! :3

corras is the only one that is informal but doesn't follow the suffix rule. correr is the verb. corre is the formal verb form. corra would be used as the formal is corre ended with an a.

your best bet would be corras, it's the only one that is informal but is still wrong